EY ENGINEER- EXAMINER C. J. KNISELY HIGHWAY SURV DEPARTMENT OF AUDITOR OF STATE Bureau of Inspection and Supervision of Public Offices A. V. DONAHEY AUDITOR OF STATE REPORT ON Economic Highway Survey ot Ohio BY C. J. KNISELY, Engineer-Examiner CoLumBus, Ouro: Tue F, J. Heer Printine Co. 1920 Bound at State Bindery, COPYRIGHT, 1920 CoLtumsus, Ouro, July 1, 1920. Hon. A. V. DonaHney, Auditor of State Columbus, Ohio. DEAR SIR:— Pursuant to your instructions of April 12th, 1920, we have made an economic survey and research of highway administration, traffic regula- tions, design, construction, failures and maintenance in Ohio. We made a personal examination of most of the improved state and county high- ways. The many failures of road surfaces this spring and the large num- ber of repairs being made by the state and counties afforded an excep- tional opportunity to examine and analyze the causes of and conditions surrounding the failures and to compare and differentiate between them. We desire to express our sincere thanks to officials and others for their many courtesies and friendly co-operation. The following report is herewith: Respectfully submitted, C. J. KNIsELy, Engineer-Examiner. PREFACE _ There are many problems connected with the development, improve- ment and maintenance of our highways and the cost of operating motor vehicles on various grades, types and conditions of road surfaces that demand immediate attention and an early solution. Under the rapid changing of transportation conditions, it is difficult to estimate the probable loads of the future, their distribution or application and no rational method has been devised for determining with a reasonable degree of accuracy the kind, nature and amount of the stresses pro- duced in different types of pavement by various traffic, climatic and soil conditions. Furthermore the amount and class of traffic, the cost of construction, maintenance and transportation are so allied and inter- woven and the conditions relating to each are so variable that the adoption of any definite set of rules or particular design or type at the present time is almost impractical. We find no definite data available by which we can intelligently design a road surface under present existing conditions. No criticism of any person or persons is intended but for the sake of clarity and argument it was considered necessary to cite specific in- stances or conditions which have furnished the basis for some of our deductions and conclusions, to point out in a logical and forceful manner certain policies and conditions detrimental to an economical and pro- gressive highway improveemnt and maintenance program, to emphasize the necessity for a prompt revision of some of the methods and prac- tices now in vogue, and to urge an earnest, practical, scientific and business-like investigation of the various elements affecting the useful- ness, cost, life and administration of our public highways. Although not all that is said may be agreed to, we hope it will offer suggestions as food for thought and which will bring about a free and open discussion of the topics contained herein and which may lead to a practical solution of the many intricate highway problems now con- fronting us. Our purpose has been to investigate and compare the vari- ous conditions affecting and relating to highway administration, traffic regulations, design, construction, failures and maintenance in Ohio and to submit for the consideration and discussion of engineers, officials and the public, certain suggestions, opinions and recommendations for im- proving the service. CONTENTS PAGE DMT eee aera cate aon Cinta e he GE ky Gio ee awd go ate ohne Pee a a 11 LTE TE Se Re, aN a a aA I ee 13 State’ Highway ME VISOL VRECAL Grenier ec cai eaten cs «at, Dee coe 18 taco On NOR Way ECONOMICS... o\e e ns) oS oe teeth oe es Ml 13 Bea Me COM MmISSIOHET Te aati iri. ce oe sol, SoU Poe ee eh ea 18 Pure FOE: Mlohw aye Department 5 Soe. 2k cae vn coe eee 18 ee ME COTW aie ety en Poe ree aig bee lig ME es 19 ie aN ARC RETR TC URGiin re EAT oii No Ne esther ts kek he gate 19 Ber Pineiietb Oty Bidsy leon ce ait See nee he ee Ct ym pee aie 19 WOT ek 209s RR mr a ee ee a NS AY 19 Meee av acer NO AS. . o. cr oe ts a! |. ela: cece Posten, shel Oe eae 19 Srading ime Advance'ot Surfacing sys. 0. ook sc keet ee 20 Boag SERRE S Rac tern ig 0 age estataray wy baby o Puen ea) Ow ae de pe 20 Proumage Oans = NMatetials /a eos 6 Oso ket os iss eeu, we ae ee 20 EIEN ihren sods Nua Mec bos ee rn dio te ha wy Aa a aa 21 rol LUE ARSE (OSE S007 pa gh OO i a A ae PEN AG RY ree aaa SPREE 7m) 22 plates nnd Nattotalakands 83 iirer ee es cows ok 8 oa ORE heb the 22 pepportioumenn Ot Flighway .Fundsso isos. ae ee Fo) oe. 23 Die eM aCe BEMIS itis arch GEN oh, sda SY Uke hee ea an ee 23 Digceee rye Og BON [SSeS 32ers how sia ety Mae en eed TO 23 Etim un ouNeel ener Accornts a. Sees! vg ee ts AL ae ee 1 23 Pe oun an tests ince Gea. 94,00 ss Sey a 8. Beit e iS Peete 25 Mice Pipnmay Muoineers ek no. a cde. cer hale shock ¢ ge 27 Se ee er rs ike cE a tons NOR re tee ee eee 30 Fe aes sade ee erred ce Go a Tc A hg EN OE Sl Bee OP acon te Me oss gi Ne ik ee Rhee by eae 82 ee Nien ee cw ase ee. age Sine oe oe ee eee te 32 Bee eatrecisn, chores Saks, bo 4) ois ch foes ing tet eee 383 fms unten Vcr rece fer Aan) Se i, hy re Ln 34 Peed, Soa e ROL ccs oe cs eh Yan 8 Gh toa ae isk ats sane aetna 34 POA, rai AMA E Siar Soe hac cy, a sb, en 34 Oe some Phrasesvand Clauses <0. 272 ld Wt ae 37 RW ashe aa eh hs oe ies ek ae ee 38 DR NO eins tia ta te Vets aes si dc ob. ee eee ae 39 eee eon sie sn j nahn. oe ew tr ial eae 39 or nell stmnates, tcc sy Goes viy he ae Oe a 40) Peete OT PERU MIE sit clcins cep vie aR sheer, « ae ee Sa en 40 eM ia eNON SE erect ee kg wig de Sysco ba ov ce SL Moe 41 es RES CST NS at SS Sg omc pee ee 4] Ne UM TIC TICES sce Ai. | ell 09) snc hae oe a 42 Pb oe cee RRC OMOMeCNM Oly ls. Sn, eee ee ee ree. 42 UL TT Ral poe Sen: AY Spe See a re oar Onan ne renee 43 Pee pe riss OR AMIOU bakes ae aut tere es gy ioe Ae. 43 [POT AS or GI Ee Sa eae a ea a a 43 ee OO ecret a S ee e 44 TOS OECTICM he 1 EN eet ep a ae oe a 44 PAGE Penalty: forViolatine —T tattic awsis omccs ha us eee mem etre at eae eee 44 Running. Trucks in’ Fleets ao. oaks, ee ee en ee ee 45 Uniform: “Trafic: Regulations an cm cect ee es ls scence elec etl Rte es cane 45 Guide. Posts ‘and! drcenseé *Raasen ween caaken eet eacnee aan ieieiore ices: eee eee 45 TELACTOLS cars ahs Bic PR apt ra ah, rca tae ke Wei ie adia, MSIE eae oe en ae AG Classification of. Roads..and. Streets: fori Trafic. 7? ¢.2 2a aes enter 45 Enforcement. of) ratic saws cose occ oul ene ee 46 “RrattiGarCOmimnissiOneine «eet nh aie tite nee cee eee eee TR ter ete 46. Highway Design: W.. <5 cos marten ere Bato org cate teat or tia se ee ain ee ee ee 47 Staite: Highway. Plans. sie cee means 2h Fa preeacn to tere a elec seperate cnn ee 47 Regquirements-In Highway. Désign sy hse fone tee einem ton ees 47 ype Of P avementaer. nat. yee Ty bd cada Sleia cata ate alte ie cece late ts aera ana 48 isreaptinie cA PeEncies |. Sessa. os ee Chita co ee eater cee mates eters 1 4Y TEGGAMOT Le ate me ere eee LSE AM CRN en Shel Pe Say pect Hi A 50 Gib i eich py ee aad oe rar on oT No a Reh Ol Pree eee Sy ary'temb Gund o's tae 51 Cleat; Sight Distances 2. cc. cic pe: s pee enema hemes Mentos be nes eee 51 Points or-Gonsideration: in- bichway-Isocattonnys ce tcess eee iret erent 52 (EF eal meats Lene iy Sr ir are PINT Ee nee ME BEALL Lar cideicim 3 54 Location: of Grades.s. 00 2., te mouse Ne Rat mene oth Sircke Grito 54 Relation of Grades. to Horse. Drawn’ Trafiicic. v:2.7ce- steer eee 54 Relationwor-Gtrades to eM Otor sl ratiic: amas eben en eee 56 Vatue- of Reducing ‘Total “(Rise rin cut sacs te sew nice note @ sete eee 58 URSA RE. weer aco as G0 eas nae pte sel ahecayee te hp ratte tale wh pe ahah cia eee 65 OBeGh roca mace EEE ea SHIRE RE Pel POH retype ew 65 Soll Saernen, esd SiapagN Tas ih oboe eed AULT Oe Jake, LE ED LGPL ea ena ee 66 a palla city >. ohio cntlaw apow iets cece vO eG KSstae ae BR ee ae 66 Peritea bility shi Sy Se one aos pate dele aly ae ieteteia Shale Regie one aes ee omer 67 SEAR aor atsete ioe foreman ae aides: Gio bide fo pea Rpee Ae CA a ee 67 SAT see ee ee oe eR OR ete RR IS eR eee 67 GLY epee eee & tak eis ea nag Bi wo ase on ake Scans ems es ane 67 (Ore hig) aes he a Aa ae Oia RN Hin oe i MOT Pls Maer eet 5G ISO Grin Go, 3 > 68 A cis eee on eee ee See CePA Penk ale denn MEL eNom e ia cI, 68 (Ejbb0 G10 (cine Pomerat Pararerl emer eee Sohne ether eee TARA Ag ore Dever outs Oh So 68 1.1, oy gl RmOearee Caer tnr ma hs hn aM ga GM Re Ninh gah PS SR nas MU re etc wOT - 68 CAPE VGE Sn tid a eet Sree ARR er eae * Saceacete on cheater eee 68 Drainage onW Grades» Essenitialiack tacks eae pterniee a cin earn 68 Farm. Crossintsy 1.22. \aran cae ot oui Bee eee eae y VG ce eee 69 Sarface Dramage: 4 rac sede cee ohne awe a nee renee nee ee 69 A BYE Leh Cy lath oe fe ee Ra Sor eA Sac ann, SON aR Cp meer here cD Cla ea ko: Oo: 69 LOW fee re eras hate IE Ah SORES the hes ane Cp eanen banner ener 70 Subsirtace Draiwtage -cfu.- c.g wage saves, = tela cate » Shanta Oakes ata mls Setero vera 72 TP Ale™ PGA eee ee cic ela: Nocde good oteae rete cee Se oenaaaNee 6 By tose GM Ae aaa Meee Melee 72 Pine Culverts rs cio sadee + ca site oe ea» Sea g Sie taka oe a Ens ore ee 73 CHIR ETES Se Ore ee a eA Tore eee ae 73 Brozen), Culverts: skis: ince s vatctcal wou area tater eitene wane Oneban them detect 73 Shomdersa-s cee nena Reieireeaee eed ats ake) kt ae 5s ee wna aR Re stale eens 74 PAV OTTLCLIES Matto one hic oe ee Ree aA na eed as ES eI OS RE 75 Width of . 5.4 ...cer Gaeta oak nea 109 Remigncttion Oot ots).0 svat ce ike oats ais HS -o dese chile pip oherg eee katana 109 Storie Ol- COMMON. cho eae ha ole he Saree eo as ae eRe ee 110 ; Cisnine” COM Pete: too 5, ck acai oC Oe ee ae ween os ee ee 110 Placinie Concrete-ii Cold“ wWeatnets (0a oct a se ot tone ee 110 Maintenance and Repair..... ede Ne red Warten PSs a be was ATE Reeords.of Costs, Repairs) fC 7.6. c%ee sake Ce ue ca ea ee eee es 111 [EWU RS he pee ee aM ae eee RM ate naa ern es ARR ACen AR Ea iy 3 5 112 CAUSE © O} MOAMICES 5 o.oo ino Fane & ele ak ee wg a eee 112 Repatring “Highways: With: Bitamensc: is i. s.u 26s .ckea alee 114 Service: Pest:od- Values of Highways. in a.aiamch oa «dete eeetienase eee 115 INTRODUCTION Road builders have not given sufficient thought and consideration to the theory and the actual construction of highways and the result of climatic and soil conditions and the action of traffic on its various phases on the road surface. Each road often presents a problem in itself on account of the variable conditions in the soil, drainage; topography, traffic, climate, material and funds available, yet there are many physical conditions and characteristics that are very similar or alike in all localities and which are regulated by natural laws, but which are not sufficiently understood. The road builder should be impressed with the fact that his work is of common use and continuously in evidence, and should make every effort to secure the best results. It is essential that the engineer come in - close contact with the proper and complete execution of his plans, so that he may become familiar with every detail of construction. This will enable him to solve many of the problems of construction and main- tenance of our public highways. Road construction requires expert knowledge and practical experience and should not be determined by prejudice, convenience or political preference. There is perhaps no kind of public improvement in which more money is expended than in pavement construction, and yet, without a doubt, no other public improvement suffers greater deterioration than our roads and pavements. Street and road paving is fast becoming a specialty in engineering and one difficult to master, for the reason that time itself is the sole arbiter. 4 Experience is principally gained by the study of both success and failures. A record of what has been done and the results should be kept so as to profit by past experience. Valuable information can be obtained from a study of materials and methods of construction which have given successful service. A comparison of the properties and characteristics of a structure which has given good service, with the characteristics and properties of those which have failed in the same service, is important. When an experiment or type of construction has proven successful, we are naturally most interested in the result and do not spend sufficient time and thought over the details and conditions which have led to the success. On the other hand, if our experiment or construction is a failure, the cause of failure is immediately sought for and every detail is questioned. It is the study of the details of both success and fatlure which broadens our knowledge. If T2 Perhaps some of the comments on engineers, contracts, specifications, etc., may seem profuse or irrevelent in this report, yet when we con- sider that many contractors and contracting organizations hesitate to bid on state work, not because of low estimates, but on account of the terms of the contracts and the manner of handling the work by the department, we believe our remarks are timely. We should attempt to build up capable and efficient contracting organizations in order to get our highway work constructed well, quickly and economically. 13 ADMINISTRATION State Highway Advisory Board There is almost a unanimous feeling prevalent that the board is too autocratic, is not sufficiently responsive to local needs and conditions, and has assumed many of the prerogatives and much of the authority that properly belongs to the Highway Commissioner, and that on account of the division of authority and responsibility, and shifting of responsibility the highway department is too slow to act and is generally unsatisfactory with which to transact business. According to law it is the duty of the Advisory Board to approve acts of the Highway Commissioner and not to act for both the Commissioner and the Board. We are of the opinion that the people of the state would receive better and more prompt service if the present Advisory Board was abolished, and the Highway Commis- sioner invested with proper authority and a Board of Highway Economics substituted for the Advisory Board. ee Board of Highway Economics There is urgent need of more flexibility in the laws relating to the letting of contracts, extra work, emergency work and other matters requiring quick action or of an administrative nature. It is imperative that more time be given to the immediate study of the problems affecting the economical administration, construction and maintenance of our highways. The people naturally hold the governor responsible to a certain extent for the administration of the affairs of the State; the auditor of state is virtually the state pay-master and should be informed as to all claims of an exceptional nature before issuing a warrant for same; the highway commissioner is directly responsible for the economic success of the de- partment; and as the board is to act as arbitrator between contractor and the highway commissioner he should be represented on the board; the various business interests of the state are vitally interested in the economic transportation over our highways and their economic construc- tion and maintenance ; therefore we are of the opinion the interests of the public would be best served and there would be less likelihood of the board becoming one sided or favorable to any special interest if’ the appointment of the four members of the Board of Highway Economics were made in accordance with the following suggestions : One “Civil Engineer” experienced in highway design, construction and economics to be appointed by the Governor. One “Civil Engineer” experienced in highway design construction and economics to be appointed by the Auditor. 14 One “Chemical Engineer” experienced in the analysis and testing of materials used in highway construction and maintenance to be ap- pointed by the State Highway Commissioner. 3 One “Engineer Economist” experienced in motor operation and transportation as a representative of the business interests of the ‘state, the name of the appointee to be certified to the Governor for appoint- ment by the Ohio Good Roads Federation, Farm Bureau and Automobile Associations. . The state is expending over twenty million dollars of government, state, county and township funds annually, yet no official of Ohio at the present time (May 1, 1920) is doing any special research work in connection with the design, construction, maintenance or failures of our highways. Any private corporation doing a business of such magnitude would have several economic engineers employed to conduct experiments and investigations with a view of improving the quality and durability of their work and materials, reducing the cost thereof and increasing the cficiency of their organization. Four practical and efficient engineers employed as herein suggested could save the state several hundred thousand dollars annually. The economic development of our highways wil require much study, research work and many experiments for several years. The board should be invested with proper authority, provided with ample funds and be assigned to the following duties: 1 — Approve all contracts for extra work. 2— Approve all claims for extra work. 3 — Approve changes in contract or plans. Few structures of any magnitude are completed in exact conformity with the original plans. Changes are often expedient because of new conditions arising from time to time, from errors, or from a proper under standing as to what was desired, or to lessen the cost or to expedite the work. There is certain to be more or less extra work, and various other items that. cannot be determined or anticipated in advance, especially for drainage and other structures the necessity of which cannot always be ascertained prior to making the excavation. The approval of extra work and other things of an exceptional nature by.engineers representing inde- pendent depatments would go a long way toward satisfying the public as to the necessity and reasonableness thereof. 4— To act as arbiter in case of disputes between the contractors and the highway department. The same laws relating to equity between individual subjects of the state should apply between, the state and its subjects. The state consti- tution authorized suits against the state but the state legislature never 15 prescribed the manner or form of instituting the suits. In the absence of sufficient legal authority of suing the state some equitable form of obtaining relief should be afforded contractors where there is an apparent injustice done them by the state. A number of able and responsible contractors are refusing to bid on state work on this account. 5 — Approve awarding contracts when bid is above the estimate. The engineer’s estimate should be a fair estimate of cost, and serve as a guide to the authorities in charge of an improvement, but owing to rapidly changing conditions and to avoid useless delays, the law should be amended so as to permit letting of contracts above the engineer’s esti- mate. This would save a lot of time, expense and delays in highway construction, Under the present law, the engineer’s estimate is assumed to be the maximum cost, but why should it limit the action of the commis- sioner? The control of the estimate is under the authority that awards the contracts, therefore the estimate should be about the actual necessary cost as near as can be determiend, and authority be given to award the contract at, below or a reasonable margin above the estimate. 6 — Approve rejection of a low bid in case of error or when made by an irresponsible bidder. | A bid received from a bidder possessing insufficient capital, equip- ment, experience and ability to do good work and compiete a contract on time should be rejected. Delays caused by inefficient and delinquent contractors usually cost the state several times more than the difference between his bid and the bid made by a responsible contractor. 7 — Study the construction, maintenance and failures of highways with a view of improving the design, methods of construction and maintenance. 8 — To conduct experiments with motor vehicles and study the action of various classes of traffic on different grades and types of pavements. g— To make experiments with road materials and record from time to time the results obtained. 10 — To sttidy various types of pavements and paving materials with a view of ascertaining their adaptability for certain classes of traffic, and, if possible, determine their comparative economic value for different classes of traffic, and develop scientific facts advantageous to the general public. There is an urgent.need of careful and thorough investigation and experiments to determine a logical basis for the design of our pavements. No scientific data has been developed relative to the fundamental. prin- ciples necessary in the actual design of pavement foundations and sur- faces. Asa matter of fact the so-called designs of pavements in use today are largely a guess based upon the engineer’s personal estimate, judg- 16 ment, experience and behavior of similar structures in service. Appro- priations should be made and ways and means provided.to determine if possible a definite knowledge of the characteristics and supporting power of various soils under various traffic conditions and types of pavements, application and distribution of loads, stresses developed, etc. Engi- neers have been earnestly asking for such information for a number of years but legislators have been woefully negligent or indifferent as to the actual and immediate necessity for such determinations. We need investigations to determine the nature of the soils and value of the materials we have in Ohio for road purposes. We cannot afford to con- tinue guessing, using hit or miss methods and investing millions of dollars under such indefinite conditions. The comparative determination of the economic value of different types of pavements under various traffic conditions is absolutely essential and badly needed at the present time. We have no definite knowledge as to which one of a dozen kinds of pavements constructed of several kinds of materials is the most economical under a certain class, classes or variety of traffic. The lack of the foregoing determinations has been the chief factor in preventing rapid progress in highway design, construction and maintenance. 11 — To make special investigation of materials furnished or work performed by contractors for the state or any of its subdi- visions when requested by the Governor, Auditor of State or Highway Commissioner. 12— To make special investigations and reports on such other mat- ters consistent with their office as the Auditor or Governor may from time to time direct. 13— To keep check and inspect from time to time work being constructed by the state. _ There are various items and conditions that frequently require a special examination or investigation by the Governor, Auditor of State, or Highway Commissioner. 14 — To investigate and report to the Governor, Auditor of State and Highway Commissioner on the advisability of construct- ing any highway or portion thereof in a county before letting a contract for the constructing thereof, taking into consider- ation the advisability of using local materials. Several roads that could have been repaired or resurfaced and placed in first class condition by the expenditure of $1000.00 to $12,000.00 per mile have been spiked up and new construction provided at a cost from $30,000.00 ‘to $50,000.00 per mile. A number of roads have been sur- faced with imported materials costing $50,000.00 or more per mile although good materials were available locally in sufficient quantities. ' 17 The interest on the difference in cost would have maintained the roads in question in good passable condition at all times almost indefinitely. It is poor economy and a flagrant waste of public funds to discard a surface on which you can drive an automobile 30 miles per hour with safety, and which can be repaired or resurfaced at small cost, and which is better than 60% of the improved roads of the state, especially when there are about 80,000 miles of unimproved roads in the state. 15 — Approve or recommend the removal of inefficient or delinquent empoyees, engineers or county surveyors employed on state highway work. Employees are more careful and alert when they are liable to be checked up at any time or recommended for removal in case of inefficiency or neglect of duties. The highway commissioner is naturally slow to remove delinquent employees under the present civil service rules and regulations, but this would not be the case if he were supported in his action by an independent board. Also employees and other officials often converse and comment more freely and offer suggestions or criti- cism to persons not connected directly with the highway department. 16 — Make recommendations for increasing the efficiency or better- ing the highway service or conditions. Many highway engineers are following the methods used by the State Highway Department without offering any suggestions for improve- ment or without regard to the suitability of the plans for the specific location or purpose, and seem adverse to offering criticisms or suggestions owing to the apparent autocratic attitude at times of some members of the department and because many engineers hope to receive favors in the way of appointments or otherwise, or for fear of losing the state’s portion of their salary. Scarcely any time is given to the study of soil or drain- age conditions. Engineers who have personal preference for certain materials or types of pavements neglect to properly maintain other types of pavements, but give special attention and money to favored types. Engineers whose appointments and tenure of office are dependent on the Highway Department are naturally partial and slow to act inde- pendently or to criticise their superior officers and their reports or opin- ions tend to be biased or colored to suit the occasion. 17—— To act as a board in issuing bonds to contractors on state and county work. Surety and bonding companies charge contractors 114% of the contract price for furnishing a bond. The sum of all state and county contracts for highway construction per year will very soon approximate $20,0000,000.00. Figuring a premium of 114% on this amount we would derive $300,000.00 per year. This is serveral times more than has been collected from defaulting contractors during the entire existence of the 18 highway department. All items entering into the cost of a contract are paid either directly or indirectly by the state. Since the state pays the premium indirectly and is put to the trouble and expense of collecting on the bonds and have been able to realize on only a very few bonds, we are of the opinion, the state would be ahead several thousand dollars | per year if the state would furnish the bonds for the contractors on all state and county work. The premium could either be feduced or remain at 114% to provide and maintain a rotary fund for completing work where contractors have defaulted or refused to complete the work. Pre- liminary to issuing a bond the contractor should be required to submit a sworn statement of his assets and liabilities and setting forth his equip- ment and cash available should he be awarded the contract. In case the contractor defauited, the state would be protected by the usual per cent retained on estimates, the contractor’s equipment, the premium on the bond, other assets of the contractor and the rotary fund. Under this procedure the state would be better able to determine who was or was not a responsible bidder. A contractor’s bond when renewed should be re- duced in proportion to the work completed. This item would save the state several thousand dollars over and above the entire salaries, office and other expenses of the board. 18 — To act as a “board of appeal” in case of dissatisfaction by any interested person, in the granting of an application for state aid by the Highway Commissioner or in the allowance of state or government funds therefore or to a county. Highway Commissioner The highway commissioner should be invested with more authority and not be subject to so many legal restrictions, and should be paid a salary commensurate with the office. He should be given more discretion in making appointments and fixing salaries, and should be authorized to appoint an auditor for the department. The salary of the auditor, secre- tary and chief egineer should be much higher so as to obtain men capable of relieving the highway commissioner of practically all of the detail work of the department in order that he may devote most of his time to economic problems, to the policy and personnel of the department and to the study of the wants and needs of the public in reference to the design, construction and maintenance of highways and bridges. Auditor for Highway Department The auditor of the highway department should have charge of all of the accounts and disbursements of the department and authority fixed by law to sign and approve vouchers for the disbursements of the depart- ment. ag Chief Engineer The chief engineer should have general supervision of all engineer- ing work of the department intluding the design, construction and main- tenace of all highways and bridges, and authority given by law to approve the payment for work without the endorsement of the highway commissioner. Reviewing Engineers The Highway Commissioner should be authorized to appoint two “reviewing engineers” to review all highway plans with reference to economic alignment, grades, width of roadway and surface, thickness of surface and foundation, use of local materials for all or part of the work, drainage or other structures and proper provisions for safety to the traveling public. They should review and approve all plans sub- mitted by the division engineers, so as to relieve the deputies and High- way Commissioner of unnecessary routine and detail work, and to pre- vent delay in the approval of highway plans. The reviewing engineers should be qualified in highway economics. Advertisement fer Bids In order to attract bidders suitably equipped to do a particular _ Class of work, the advertisement for proposals as published in newspapers should be more specific as to the kind and nature of the work, amount of each item or class of work and estimated cost thereof, length of haul, railroad stations, shipping facilities, current price of labor, materials, freight, etc., payment of estimates, acceptance of part or of all work as completed, local supply of materials, water, housing conditions, street, railroad or other facilities, work adapted to the use of certain kinds Ole = equipment such as steam shovel, dragline, etc., and such other facts rele- vant to the work. Patented Pavements The construction of patented pavements may be justified in some instances, but it is very doubtful as to the state being warranted in adopting a policy of constructing patent pavements. Where patented pavements are contemplated the royalties and terms thereof should be made a part of the estimate and the authority in charge of the improve- ment should guarantee the amount of royalty to be paid by the contractor and the terms thereof. Main Market Roads On account of the division of authority and responsibility and large amount of through traffic on our “main market roads” we are of the opinion the state should take full charge of the construction and mainte- nance of all the “main market roads”. The Highway Commissioner should have full control of the personel employed on the design con- 20 struction and maintenance of all the “main market roads” and be held responsible for the condition thereof. Grading in Advance of Surfacing We are of the opinion that if the state would adopt a policy of grading and carefully and thoroughly draining the roadbed a year or two ahead of placing the surface thereon, the cost of maintenance and repair would be materially reduced. This might result in some incon- venience to the traveling public and a slight additional cost of construc- tion, but in time it would be a paying proposition. It takes earth from one to three years to assume its original density and volume after being disturbed. The nature of most road grading is such that it is not possible to obtain a uniform density of the subgrade and roadbed, hence, there is bound to be uneven settlement resulting in lessening the supporting power of the subgrade at various points and increasing the stresses in the foundation at these points. This procedure would give the roadbed time to settle and for adjustment and to assume its natural density. Also afford an opportunity to examine the roadbed for any deficiency in drainage and to provide for any additional drainage necessary before placing the finished surface thereon. Unequal density and irregular dis- ‘tribution of earth of variable characteristics result in unequal settlement, absorbtion of moisture and expension by frost, any or all of which tend to produce displacement and cracks in pavements. Assessments The law relative to making assessments on abutting property where state aid is furnished should be amended so as to permit inaking part of the assessment at one time and the balance from one to three years later. The object being to grade the road and construct the drainage structures and, if desirable, construct a temporary surface of gravel, slag or stone which will act as a foundation for a high class surface at some future time, and then make an. assessment for the cost of the grading, drainage structures and temporary surface. This procedure would give the roadbed time to settle, consolidate the foundation, de- velop deficiencies in drainage, and accommodate travel during the interim. Use the temporary surface until it begins to need slight repairs, then select the type of pavement for the finished surface, construct the same and make another assessment for the cost thereof. Promoting Roads, Materials, Etc. There is considerable complaint by various officials on the methods pursued by some materials interests in promoting materials used in high- way construction. - Manufacturers and others interested in the sale or use of a certain material in advocating the exclusive use thereof for all purposes and dis- 21 crediting all others are pursuing a policy detrimental to a progressive highway program. There are limitations that should be set for all ma- terials beyond which the use thereof is not practical. A company can- not profit for any length of time in promoting or selling a material for purposes for which it is not adapted. The company and the public would both be ahead to limit a material to its practical use. When each one of several material interests magnify the quality and uses of their own materials and show up defective pavements constructed of their competitors material they set up a doubt in the public mind as to the practicability of constructing any economical type of pavement. Promotion of materials is alright in introducing a new material or new design or in calling attention to the merits, economy and adaptability of a material for a certain class of service. Many thousand dollars have been lost in road failures ofall types that might have been saved had material interests given more attention to the manufacture and use of their materials. Several materials would now have a higher standing among engineers and the public and be in more demand today had the failures not occurred. We believe that if the manufacturers of road building materials would expend Jess money in promotion and would devote more of their time and expense in a study of how they might improve the quality of their materials, purposes for which they are best adapted and to improve the methods of construction, more satisfactory results would be obtained and there would be less need of promotion work. Companies quoting contractors or contracting to deliver material for use in the construction of a highway, or bridge and then withdrawing the quotation after the acceptance thereof, cancelling the contract or re- fusing to deliver the materials deserve to be severely criticized for such practice. If material and labor have risen in price the selling company should stand by their contract and not put an additional loss on the con- tractor. Selling companies usually have many opportunities to offset any loss on a contract by the large number of sales while a contractor ‘may have but one contract. The state and public have been put to much inconvenience, annoyance, delays and expense by the aforesaid practice. Possibly the prices for all materials used in each contract for highway work should be filed with the highway department with a bond guar- anteeing the quotations and delivery of the material. The material in- terests have required the state to practically guarantee the payment of materials used by the contractors on public work so why should not the state require the materials companies to guarantee the prices and delivery of the materials to the contractors ? Financing The principal factors which enter into the economic efficiency of any improved road are the initial cost of the improvement, the cost of mainte- 22 nance and renewals and the saving in cost of transportation. The financing of road improvements is rapidly becoming of vast importance. It necessarily involves consideration of all operations of construction, repair and maintenance, and the repair and maintenance charges should be considered at the time of selecting the type of pavement. Many engineers are apt to build expensive roads. They like to see what they term a “finished product”. This is a common fault and fre- quently results in poor economy in highway construction. In highways, as in railroads, we should sometimes consider the economic principle, that it is sometimes better to make an entire community accessible by constructing a more extensive means of communication and to let the added prosperity raise the standard of construction and maintenance as the exigencies of the traffic may require than to leave part of it inac- cessible by building only a limited number of miles of expensive con- struction. The alignment, grade, earthwork, drainage, foundation, culverts and bridges of certain kind may be regarded as permanent but there is no such thing as a permanent road surface. Traffic and disintregation from natural causes render any road surface subject to repair or renewal at some time or other and adequate provision should be made for such repair and renewals as the same may become necessary. High Cost Roads Something must be done at once either to reduce the cost of our highways or to reduce the maintenance and increases the life thereof, ‘or to limit certain traffic to particular roads. They are not giving the service the expenditure therefor would warrant. There are over 90,000 miles of highway in the state, which at a cost of $50,000.00 per mile to construct and the maintenance incident thereto would require several huridred years to improve them all and would in time bankrupt our town- ships, counties and state under the present system of regulating high- way trafhe and providing funds for highway construction. State and National Funds The use of state and national funds is justified on all types of con- struction so long as the use thereof aé¢tually improves fundamental high- way conditions and meets the requirements of the general scheme of transportation. The State, Government and Counties of high valuation should assist in financing improvements in counties of large area or low valuation. The Government helped build some railroad lines in isolated territory and has reaped untold returns on the money expended. With- out such assistance it will be impossible for many of the counties to build more than a small percent of the mileage of the roads without incurring obligations that will be a serious menace to the progress and prosperity of future generations. 23 The State and Federal Government should pay most of the cost of the construction and maintenance of through routes and main market roads of the state, and more of the county money expended on feeders to these highways. Apportionment of Highway Funds The apportionment of federal and state funds to the various coun- ties should be fixed by law in some definite form or apportioned by an economic engineer designated for the purpose so as to stop trading and bartering between counties and types of pavements. Maintenance Funds — - Maintenance should always be paid from current revenues, such as taxes, licenses, etc. and never from bond issues or general funds. Any other proceedure would naturally lead to bankruptcy. When a contract is let for the construction of any type of pavement, arrangements should be immediately made for the maintenance thereof. Highway bonds should not be issued for a longer term of. years than the life of the highway. A “pay as you go policy” should be fol- lowed as closely as possible. Where bonds are issued, a “serial bond” will usually be found to be the most economical. When highway bonds are issued it should be definitely understood that in addition to the tax for the interest and retirement charge there will be a tax for repair and maintenance. All highways, regardless of type require more or less maintenance. “ Necessity of Bond Issues Highway improvement is more often an investment than a con- venience as it may be economy to pay an interest charge and have the use of a road at once than to pay for the increased cost of. transporta- tion on a poor highway, or it may be advantageous to build roads in long stretches or to make connecting links on certain through highways. Paying and Auditing Accounts On account of the necessary delays due to our present arrangement of auditing and paying accounts to the Highway Department in the various counties of the state and to additional delays due to errors which necessitates returning the payroll one or more times for correction and which takes several days and sometimes weeks for correction and fre- quently considerable correspondence which at best is not very satisfactory, and on account of the difficulty of obtaining and retaining efficient men under these conditions and to avoid unnecessary inconvenience to the men for an indefinite length of time and to prevent employes from being coerced into approving bills that they believe are not right and proper by those over them in authority, we recommend that the Auditor of State designate three traveling engineer examiners with authority to audit and 24, issue warrants for payment of all payrolls material and supply bills of the Highway Department. If any of the payrolls require the approval of the Civil Service Commission we recommend that said traveling en- gineer examiners be vested with authority to act for the Civil Service Commission in approving highway payrolls. Being engineers they could frequently check and examine the work and in addition to auditing the accounts would be able to judge what was a proper charge for both the quality and quantity of the work con- structed. Being in close touch with the work at all times would avoid delays, facilitate the work, and remove excuses for and correct question- able practices and abuses which may not be technically wrong but which are not in accordance with good business practice. A number of things would be checked that otherwise would be passed by and many conditions that induce temptation and lead to grafting would be obviated or removed. Pay days should be designated consecutively in adjoining counties so as to provide a convenient and continuous route for the auditors. Business houses, railroads and other corporations have their traveling auditors and paymasters so why should it not be advisable and practical for the state to do likewise and especially since the funds available for highway construction have become so enormous. Under the present system the County surveyor O. K.’s bills and pay- rolls on the strength of the county road superintendent’s O. K. The Highway Commissioner O. K.’s bills on the strength of the County Sur- veyors’ O. K. and State Auditor in turn issues warrant if bills and pay- rolls are correct, regular and appear reasonable. Funds for payment of salaries and expenses of Auditors could be provided at once by the Board of Control transferring or appropriating sufficient state highway maintenance funds for said purpose. We recom- mend this system of paying state highway accounts be inaugurated at the earliest convenient date practical. The adoption of this system would save considerable time and expense on the part of road superintendents, CountySurveyors, State Highway Department, Auditor of State, and would facilitate highway work. 25 Division Engineer’s Office There are approximately 18 engineers now employed in the Con- struction and Maintenance Department of the Highway Department. We are of the opinion that the State should be divided into 18 divisions (instead of 11 as at present) of not over 5 counties each and an office be provided for the Division Engineer in each Division. The office could be easily arranged with very little if any additional cost to the State. The County Surveyor and County Commissioners would gladly furnish desk and office room and the use of a telephone, surveyor’s equipment, stenographer, etc., when required in consideration of the many additional advantages to be derived by having the Division Engineer within easy reach at all times. The office should be conveniently located with ref- erence to easy communication by rail and highways with all the counties of the division. The division engineer should have charge of the Construction, Maintenance and repair of all highways and bridges of his division and should be invested with proper authority and be held responsible for both the progress and quality of the work. This would avoid much duplicity of work and traveling and would give the division engineer sufficient time and a chance to study and analyze the cause of failures and correct defects in design or methods of construction. The engineer who makes the repairs has by far the best and most practical opportunity to study road failures and defects and to offer suggestion to lessen or obviate them: and for this if no other reason should have charge of both maintenance and construction. Almost without exception engineers have neglected to take advantage of such conditions and circumstances to improve our methods of highway design and construction. Under the present system, the division engineers lose entirely too mucth time traveling and at Columbus and consequently do not devote enough time and attention to the actual work of construction and repairs and studying highway conditions with a view of improving the usefulness and life of our highways and reducing the cost thereof. We are of the opinion a division engineer should be fully competent to supervise the construction and maintenance of all highways and bridges in a division under the direction of the deputies of construction, maintenance and bridges. In order to obtain good work and improve our methods of highway design, construction and maintenance it is abso- lutely necessary that the engineer come in close touch with the execution of his plans; this is very essential if we expect to build more durable and, economic highways. The resident engineer, county surveyors, road superintendents and others have too much trouble and lose too much time in getting in com- munication with the division engineers and experience too many delays 26 in road work, making highway plans, estimates of cost, contractors esti- mates and in getting prompt action and decision from the division engineers. According to present practice the division engineer is for- tunate if he gets around to each county more than once in about every ten days. In several instances the reisident engineers: have waited from two to four weeks for the division engineer to fix the grade line before they could proceed with the completion of the plans. The division engi- neers according to the present arrangement have entirely too much to do and too much territory to cover to give the work under their direction and supervision, the personal attention and consideration necessary for rapid progress and economical highway construction. “A few months’ delay in making a survey or letting a contract may mean much incon- venience to the traveling public and add several hundred dollars to the cost of the improvement. By having fewer counties in a division, the division engineer would be able to personally inspect, check and promptly approve highway plans, estimates and payrolls, which would generally facilitate the highway program and avoid many annoyances and use- less delays. On account of the great difficulty of obtaining satisfactory and efficient inspectors and consequently a lack of uniform inspection and supervision, and in view of the fact several county engineers are con- templating placing an engineer on the work in lieu of an inspector, and the construction and maintenance of our highways being so closely re- lated, we believe our suggestion should be followed. We believe the salary of the division engineer should be much higher and sufficient to attract good engineers and so they need not worry or engage in outside work, to make a decent living and a margin for saving, but could devote all their time thought and energies toward improving our methods of de- sign, construction and maintenance and studying economic conditions af- fecting our highways. In lieu of dividing the state into 18 divisions the state might be divided into 14 divisions of 5 counties each and two divisions of 9 counties each. The two division engineers having 9 counties to a division should each have an assistant engineer. The only advantage to be gained would be in having two engineers trained in case of a vacancy in the office of Division Engineer. We would not recommend this procedure for all of the divisions as it eliminates the most important item in highway construction that is “keeping the engineer in close contact with the execution of his plans’, so as to correct faults in highway design and construction. The Civil Service rules should be modified so as to permit the ap- pointment of division engineers to be made at the maximum salary and permit appointment of county surveyors and other qualified engineers. An engineer capable of filling the position of division engineer is not likely to enter the service at a low entrance salary. 2] The Highway Engineer The Highway Engineer should keep well informed on the manu- facture of materials used in road construction in the mechanical ap- pliances used in building roads, on the methods used in the laboratory for testing various road materials and should be acquainted with the laws and systems of administration; he should supplement these qualifica- tions by reading, study, practical experience in both field and office and by experiments with various methods and materials of road construc- tion, and should devote considerable time to the actual building and con- struction of roads so as to become familiar with every detail. To attain and maintain proficiency requires close and constant study, hard work, careful investigation and personal inspection of roads and streets in various localities under service, their construction, and analysis of their component parts. ; The engineer has need of much tact, diplomacy, patience, judgment and firmness. He should make his plans and specifications so that he can defend them at every point and be able to overcome any and all objections from contractors, officials, public or property owners. He must protect the public by providing adequate plans and specifications for good work, and must aid the contractor in securing it. To do this he should know definitely what he is doing, and how it should be done. An engineer should be assistant to the contractor and not his persecutor as is too often the case. . If the engineer is actually able to prosecute the construction with equal speed and economy and at the same time obtain equal or better results than the contractor actually doing the work, a large amount of friction and dispute between the engineer and the contractor would be avoided. An engineer should never let his judgment be swayed by prejudice. He should be willing to recognize and acknowledge beneficial ideas and suggestions from whatever source they may come. The engineer should be gifted with the power of analysis of facts, as well as with the power of drawing conclusions from the data at hand. He should be ingenious in devising methods to demonstrate the points at issue, and a careful observer at data. He must keep himself free from bias or prejudice, and take especial pains that he does not deceive himself. He should keep constantly in mind the end to which his experiments tend, and understand clearly the effect of every step in the progress of his tests, and its in- fluences on the final result or conclusion. He should not only know the method and manipulation, but also know the reasons why, and the prin- ciples underlying the method. The engineer who knows methods and manipulation gets along fairly well as long as everything goes well, and may turn out more work in a day than a thinking and observing engineer, who understands the reason why for every step in his analysis or pro- 28 cedure ; but let a difficulty arise and the methodical engineer is absolutely lost. The one has stored his mind with facts and has learned the methods and manipulations required. The other has acquired principles rather than a large array of facts, and he knows the reason why. An engineer should not only be proficient technically but should be efficient commercially. An engineer often directs the work of others, therefore he should have a knowledge of business methods and the motives that influence men and some experience contracting. The engi- neer should remember that according to most contracts and specifications, he is made the “arbitrator” between the principal and the contractor. Therefore, he is in the employ of both parties of the contract, altho’ the principal according to common practice pays the contractor’s portion of the fees direct to the engineer. Otherwise the contractor would include the engineer’s fees in the amount of the contract price for his portion of the fees to be paid the engineer. The engineer should be responsible for the accuracy of his estimates and his plans and specifications and his instructions as to the manner in which the work is to be performed. Do not hold the contractor re- sponsible for mistakes of the engineer or the principal, or for conditions over which he has no control. Accept and pay for all work and material which has been done according to the directions of the engineer, or his authorized agent. If the contractor has substantially complied with the contract according to the engineer’s instructions he should be paid for the work although the results obtained are not as were anticipated by the principal or the engineer. | He should be fair in all of his interpretations, instructions and de- cisions regarding the contract or the work, so as to keep the contracting parties out of litigation. The engineer is often given much authority and discretion under our present contracts and has greater power than the courts because he may decide contrary to law, and still have his judgment stand, therefore, his decisions should be beyond criticism or reproach, for he takes the place of the court and his action may close the way for either party to appeal from his decisions. If the engineers were always fair in their decisions and instructions and would make the plans plain, the specifications clear and concise, and free from questionable, am- biguous or objectionable clauses, and their estimates accurate, most of the troubles and disputes relative to construction contracts would be eliminated. . The price which a contractor can afford to bid is often determined by his knowledge of the engineer in charge of the work. This should not be the case. Bidders have a right to know just what is intended and the per- sonality of the engineer should not have to be taken into consideration. Frequently engineers are so afraid of their reputation that they try to 29 hide their mistakes from the public at the expense of the contractor or by inferior workmanship and material. No engineer should hesitate to acknowledge an honest error. No one is anfallible. ‘Honesty is not only the best policy” but is the only policy. The engineer should look after all work carefully so as to avoid having any work completed in a poor or unsatisfactory condition and should inspect and report promptly on all materials so as not to delay the contractor in the execution of the work. 30 INSPECTION The inequality in inspection is very noticeable and much of it could be eliminated and better quality of inspection and work obtained, if care were taken to accurately state what is meant and intended and a proper explanation of the purposes of the various clauses in the specification were given to the inspectors instead of leaving the specifications to the interpretation of the inspectors and contractors. Clauses in specifications are frequently neglected, overlooked, mis- interpreted or considered of little or no omportance due to insufficient knowledge of the principles involved and to a misconception of their application. for the benefit of inspectors, engineers and contractors, a pamphlet should be published discussing the underlying principles of the different classes of construction, explaining the reasons for the various clauses in the specifications, emphasizing vital points necessary to be observed And calling attention to the results that will follow if the work is not constructed according to the specifications. It is not necessary for an inspector to raise “particular hell” all the time to get good work done or to satisfy the public he is doing his duty. Have a definite and clear understanding how the work is to be done before beginning it. Settle the differences or disputes before doing the work, not afterwards. It is costly to replace work or make changes after work is commenced. An inspector should not be allowed to give any instructions to the contractor unless he is experienced and well qualified to do so and the engineer is willing to assume all responsibilities for such instructions. The duties of an inspector on the work are to see that the specifica- tions, plans, and contract are faithfully fulfilled and that all work and material is of the class and character specified and to keep the engineer informed as to the manner and progress of the work. He should have no jurisdiction over the workmen but should report at once in writing any departure from the specifications, plans or contract to the contractor or his representative on the work and to the engineer. Inspectors and engineers should avoid as much as possible giving instructions and directions to the contractor or criticising the work in the presence of workmen, strangers, etc. It will usually be found better to have the contractor make corrections apparently at his own instance than for the engineer or inspector to act through the workmen. A con-. tractor may be trying to do right and having feelings as well as others would naturally resent being bawled out before his men under those circumstances. An inspector can be firm, honest, diligent and courteous at the same time. 31 Inspectors should be trained, paid an adequate salary, and as far as practicable be employed continuously and in any part of the state. Contracts There are five esesntial elemtns to a contract, viz.: Ist— Two or more parties with the capacity, right or authority, to contract. 2nd—A . lawful consideration. 3rd—A lawful subject matter. 4th— Mutual assent. 5th— Time when of the essence of the contract. Many forms of contracts for public work in a common use frequently contain sentences and paragraphs that are absolutely, unfair to the con- tractor and which are never included in contracts between individuals. These clauses seek to make the contractor liable not only for his own mis- takes and misfortunes, and the ordinary hazards of construction, but, in unmistakable terms, fasten upon him the liability for the errors, ineff- ciency, or carelessness of the owners, agents and employees. Fair and equitable contracts and specifications and accurate estimates secures cheaper construction and the contractor can be held to his work more easily. Contracts should be drawn with due regard to the rights of both parties,-and the state, counties and municipalities should assume for their agents that responsibility which they demand of the contractor for his employees. Many specifications carry this same defect or refusal upon the part of the State, County or Municipality to definitely define and, assume its own responsibility. Throughout most contracts you will find the clause “and to the satisfaction of the engineer.” Define just what is intended ‘and wanted and relieve the contractor of the varying ideas, and shifting fancies of the different engineers and inspectors. Of the same class is the oft-recurring phrase, “or as ordered by the engineer” some- times necessary, but frequently as a shield to protect the engineer from his own hastiness or mistakes and place the burden on -the con- tractor. Such clauses make the engineers’ estimate worthless. The State, Counties and Municipalities should be bound by the instructions or orders. given to the contractor by its engineers and inspectors. An engineer should seldom be made the sole referee in settling all claims. He is usually retained and employed by the state or owner to make the plans and specifications and it is but antural he would interpret them according to his own intent. The difference in the interpretation may be the profit or loss on the work. Being a paid employee of the owner in the first instance it is not unreasonable for the contractor to expect him to be biased in his opinions and judgment. Furthermore, plans and_ specifications are often indefinite and incomplete and when placed in the hands of an inexperienced or incompetent engineer or inspector may work a hardship on the contractor or result in the payment for inferior work or materials. Treat a man fairly and nine times out of ten he will not try 32 to take an unfair advantage, but it is “inherent in human nature for a man to attempt to beat a game framed up to beat him.” 5 The Contractor Contractors should not take contracts at too low a figure. Better be sorry you did not get a contract than to be sorry you got it. Do not sub- mit bids on work where the specifications and contract contain unreason- able clauses. If the engineer or his employer does not assume responsi- bility for the correctness of the estimate or make provision for errors or unforeseen contingencies why should you assume such responsibility? If the engineer or owner believes the estimate is correct, why should he object to being held responsible or to make provisions for equitable pay- ment in case of error? If the engineer does not believe the estimate cor- rect, then why should the contractor believe it? Furthermore, the con- tract is dishonest. A contractor is not supposed in the limited time allowed to make up his bid to make a detailed survey and estimate which took the engineer weeks or perhaps months to make. Contractors should not take contracts so large that they cannot readily finance them; to do so means loss of time and money. It requires ready cash equal to at least 25% of the amount of the contract in addition to the equipment necessary to carry on a contract successfully and with economy. A contractor should comply with the terms of the contract and speci- fications and should know when he has met the requirements thereof and not depend upon instructions from the engineer or inspector. Never receive orders of instructions of a special nature from an inspector or engineer unless in writing, and do not follow them if not according to the terms of the contract. When a contractor has entered into a contract to perform a certain work in a certain manner, using specified materials, he should perform the work accordingly regardless of his own opinion as to how the work should be done or the materials to be used. It is a con- tractor’s business to execute his contract and not to give out opinions concerning the work or the materials used or the success thereof. It is the duty of the contractor to see that all the materials he buys meets the specifications. Make the terms of your contracts for the pur- chase of materials such that there will be no necessity to crowd the limits of the specifications, or to attempt to use inferior material or to claim loss in case of any rejected material. Extra Work If a change will add to the value or to the usefulness of a structure the change is evidently desirable. If it will impair the structure in any way, the change is not desirable. Do not make changes and pay for them by a “give and take method.” Determine the cost before making the changes and arrange for payment of same in a legal manner. Changes should be reduced to a minimum as they are usually an annoyance to both 33 the engineer and contractor and often entail an intangible cost to a con- tractor. Contractors should remember that an engineer cannot render the state or county liable for extra work without express authority in writing and a certificate from the proper person or officer that there are funds available for the payment of such extra work and the order for such extra work must comply with the terms of the contract and be legal. It is an engineer’s duty to see that the contract is properly executed and completed and he cannot order extra work performed in addition to that expressly provided in the terms of the contract. A clause providing that. the work shall be done under the direction and supervision of the engineer in charge, confers no authority upon the engineer to change or modify in any essential particular the provisions of a contract. The only safe course to pursue for extra work is to make a new or supplemental contract according to law and in writing for extra work or for changes which require additional costs or where there is a material change in the plans or method of doing the work or where the results may be different from what was intended in the original contract. A contractor cannot recover in court for work performed which is not according to the contract, specifications or law, though performed under the direction and orders of the engineer, not even if the contract contains clauses authorizing the engineer to make changes, modifications and alterations and states that the work shall be done under the super- vision and direction of the engineer and to his satisfaction and acceptance, Cost Plus Contracts There are three serious objections to cost-plus contracts. Ist. Manner of obtaining the contract. 2nd. Incentive to keep down cost. 3rd. Incentive to complete work on time. Where the work is of such a nature that a cost plus contract is de- sirable we suggest a sliding scale for payment and advertisement for bids to determine the bidder. Advertising for bids for actual cost of work, based on engineer’s esti- mate of quantities and amount and kind of equipment required. Allow the contractor a tentative profit of 20%. of price he bid. To determine the contractor’s actual or net profit add to or deduct from the tentative profit allowed him, as the case may be, 25% of the difference between the actual cost and the contractor’s bid for cost. Require contractor to furnish a general superintendent at his own expense. Under the above form of contract every dollar the contractor expends uselssly 25 cents comes out of his own pocket and every dollar he saves adds 25 cents to his profit. The quicker he completes the work the more profit he will make as he ' will be relieved of superintendent’s salary and the sooner his equipment will be released for other work, as 34 Force Account Work The highway commissioner should have full power and authority when in his opinion the interests of the public would be best served to construct any and all work by “force account.” By “force account” we mean at actual cost and not “cost plus a percentage” or delegating some contractor to act as agent for the Highway Department. This would give the highway commissioner a leverage or a method of procedure in case there was a collusion of bidders, bids too high or no bids received. ° The highway commissioner should be authorized to build up several efficient construction and maintenance organizations. Defaulted Contracts Where a contractor has failed or refused to complete the work and in order to protect a defaulted contractor and his bondsmen and to prevent criticism of the department in certain cases, perhaps advertised bids shoulds be received for the completion of the contract. In case the highway commissioner was of the opinion the bids were too high, the highway commission should be authorized to complete the work by “force account” not “cost plus a percentage,’ but in this case the cost to the bondsmen should not be in excess of the amount of the lowest responsible bid recéived for the completion of the work. Specifications The purpose of all specifications should be to enable a contractor to understand what the owner wishes to have done or performed so that he may execute the work accordingly. Every sentence in a specification should be written with the idea of making everything clear as to what is intended on the part of the owner and what is to be expected by the con- tractor. There should be no ambiguous sentences or clauses in a speci- fication for these are the ones which cause friction between the contract- ing parties. A sentence that is not clear in its meaning should be omitted in a specification, Specifications should be written in a simple, concise language, admit- ting of but one interpretation. They should be fair to both contracting parties and should be so worded as to prevent an unjust engineer from exacting unfair requirements, as well as to prevent an irresponsible or inexperienced contractor from using inferior materials, or performing inferior workmanship. It is a common practice with an engineer, in his desire to protect his employee’s interests, to frequently insert clauses that are unfair to the honest contractor and which often invites trickery on the part of an unscrupulous contractor. The engineer in preparing the plans and specifications and informa- tion to bidders assume the responsibility not only of the design of the structure but also of imparting to the contractor definite, accurate, and detailed information as to the amount and quality of material needed, the Sh) general method of placing or performing the work and a fair method of determining whether or not the contractor is furnishing what is called for by the plans and specifications. The engineer in imparting information should be very particular to give accurate and full information of his requirements of the contractor, otherwise the contractor can not determine what the proper cost will be, and he must assume a risk which is not proper for him to assume. The contractor shou:d assume responsibility for costs of materials, handling of labor and materials, equipment and natural conditions at the site. A workable specification should contain such information as is needed by the manufacturer, by the inspector, by the chemist, by the engineer, and by the contractor. The fewer possible restrictions that a specification contains and at the same time affords the necessary protection in regard to the quality of the material and work, the better the specification is. A common fault in specifications is in making the limits too severe. The success or failure of structures, or materials in service usually do not depend on extreme figures. It is better to make the limits of the speci- fications wide enough when they are first drawn, so that they will cover all the uncertainties in manufacture and use of an inferior product or performance of inferior workmanship. Excessive limitations in a speci- fication lead to constant demands for concessions, which must be made if work is to be kept going, or to more or less successful efforts at eva- sion Better a few moderate requirements rigidly enforced, than a mass of excessive limitations which are difficult of enforcement, and which lead to constant friction and sometimes deception. : It is not fair nor right for the contractor to ask the engineer to accept work or material which is not according to specifications neither is it fair or right for the engineer to ask the contractor to use materials ot methods of construction or perform extra work not provided in the esti- mate or not according to the plans and specifications. The State or owner has a right to assume that every bit of the mate- rial and workmanship meets the requirements of the specification, since this is what he contracted for and expects to pay for. If a specification is so severe that only two-thirds of a well made material will stand the test, the specification should be changed ;and if a manufactuer can only make a product, two-thirds of which: wil} stand test, he should learn how to improve his product. Material or work once fairly rejected, should never be accepted or used. It is unfair to those who are furnishing material or construction which fully meets the require- ments, to accept material or.construction*¢rom others who fail in this respect. a Manufacturers should work far enough within-the limits of the speci- fications, so that the inevitable and unavoidable errors of testing would never lead to the rejection of a shipment. The limits of the specifications 36 should be sufficiently wide to cover the unavoidable and inevitable errors of testing. Never reject a shipment unless you know beforehand, that so far as the figures of the test are concerned, you will win in the contest which may follow the rejection. If material or work has been wrongly rejected and the shipper or contractor has been put to expense in regard to it, the state should make the loss good due to the erroneous rejection. Do not waive specifications but make them fair so they need not be waived. In writing a specification an enginerr should take into consideration the interpretation a contractor may take regarding the various clauses of a specification and the varying meanings the same words may convey to different minds. Persons whose interests are naturally and ligitimately opposed will attach different meanings to the same words and yet the parties may be equally honest. An engineer shauld be the best judge as to the intent of the specification but he should make them plain and clear that the bidders will interpret them with the same intent and purpose as the engineer. The weakness of most contracts and specifications is that the engineer seems to be too afraid of his reputation and spends too much time in preparing stringent clauses to project himself from his own mistakes and acts, instead of making the plans and specifications clear, plain and complete. The very essence of a contract is mutuality; and the more this im- portant principle of a contract is kept before our minds the more faith- fully will the contract be carriedout and the less will the friction develop. The more you go into detail and the tighter you make a contract in cer- tain points, the weaker it is with regard to those considerations that may develop that are not covered in detail. It is in the actual construction where the faults and shortcomings of the engineer’s plans and specifications and the contractor’s estimating ability to show up. Here is where the differences in the interpretations as to what the engineer has actually said and as to what he had in mind when he wrote them and therefore should assure himself that he has clearly and concisely informed the contractor though the plans and speci- fications as to what would be required. Neither the state, nor the engineer should have any control or direc- tion over the progress of the work, not the control or superintendence over the machinery or plant; the responsibility for the proper handling apparatus, ways, works, men, of which, as well as for the safe and proper conduct of the work, resting solely with the contractor. The engineer who prepares the specifications for a contract, knowing what he wants in the way of a road or bridge and.of what materials he wants it to be built should describe not only the actual location of the road and its grades and cross sections but should investigate the sources of materials. He should point out to contractor what materials will be 37 accepted, where it may be found, either along the line or within reach- able distance; the stations of the railroads most accessible to the sources of supply of material, and the highways by which access may be given. Such information would result in lower prices in many cases, and would prevent the presentation of bids at too low a price because of lack of information with the result that the contractor fails and the work must be relet with the delay and additional expense incident thereto. Appropriate barrow pits where necessary should be located by the engineer and their location pointed out to the prospective bidders to insure fair play between all bidders, any and all royalties, permits, leases, rights of way, etc., should be negotiated in advance and the costs set forth in the information given. If the engineer has any idea that the specifications and estimates do not represent or are not likely to represent the true character of the work within reasonable limits, then such clauses should be inserted in the con- tract as will give the contactor the right to demand that for unreason- able discrepancies the work shall be paid for at cost plus a reasonable mar- gin of profit. Questionable Phrases and Clauses The engineer should bear in mind that clauses providing “that the work shall be completed to the entire satisfaction and acceptance of the owner or engineer” or “the engineer’s decision shall be final without re- course of appeal” do not possess essential features of a binding contract and are held to be void even though the contractor has agreed to such terms, for the reason that they are in violation of the constitutional rights of citizenship and usurp courts of their proper jurisdiction. Parties can- not by an agreement in advance, when no dispute or controversy has arisen, forfeit their rights to a proper adjudication in a court of equity. The right to resort to the courts for protection and relief is a constitu- tional right guaranteed to every citizen. It is a right that neither the state, its legislature, nor an agreement between themselves can impair. Clauses such as the following should not be included in a contract or a specification as they are unfair and unjust. “Any work not herein specified which may be fairly implied or included in this contract, of which the engineer may be the judge, shall be done by the contractor without extra charge.” Where such clauses appear a contractor would be justified in insert- ing a similar clause. “Any work or item of cost forgotten or omitted in the bid which may be required to complete the contract, the state shall pay for such extra work at a price fixed by the contractor.” One clause is just as fair as the other but neither clause has any place in a specification or contract. Engineers should not rely on cor- recting clauses to cover their short-comings, 38 Avoid general terms or blanket expressions such as: “satisfactory to the engineer,” “first class work,” “satisfactory work,” “as directed by the engineer,” “if deemed necessary by the engineer,” “according to terms or conditions prescribed by the engineer,” “at the option of the engineer,” “right to change plans without invalidating contract,’ “engineer reserves right to direct sequence of the work,” etc. 9? 66 Estimates The engineer should be very careful in publishing the estimated quantities. It is the practice of many contractors when bidding upon important contracts, to check the quantities accurately, but the engineer usually has more information available and it is unfair to the contractor if he does not make his estimates accurately and publish the facts. But very few of the engineers’ estimates are accurate and are seldom verified by the costs of construction. . The fundamental basis of competitive bidding is in accurary of plans and estimates. In justice to the contractor, the owner should assume responsibility for estimates, or at least provide for some equitable arrangement bywhich -a contractor is not held responsible for them. Do not overestimate the cost, and thereby restrict work on account of its apparent cost, nor carelessly underestimate the cost, and thereby bring disappointment, loss and sometimes total destruction to the owners or contractors. Shift the design, change the materials and alter the plans so as to reduce the cost, when necessary and thereby bring the cost to the point where the results obtained will justify the expenditure, or be within the money available. The contractor should receive a dollar for a dollar’s worth of work and he should not be expected in the limited time allowed him to check and duplicate investigations made by the engineer during a protracted period. The engineer should assume rsponsibility for his designs and the contractor should assume responsibility for their executions. Contracts should be drawn so that they may be automatically and not autocrat- ically modified to meet actual conditions as the work progresses. For this reason the engineer should be most careful to point out the difficulties to be encountered when he prepares his schedule of information to be furnished prospective bidders. The engineer’s estimate should be made part of the contract. This would fix upon the engineer the responsibility of making a correct esti- mate and the contractor should not be held for errors in the estimate or for unforeseen contingencies. The preliminary survey should be made with the utmost care and the plans and specifications drawn therefrom should be the subject of the most careful thought and study, and when finally adopted should not be lightly changed. 39 When the approximate estimate in specifications shall have been exceeded by ten percent, the unit prices bid upon the work should no longer prevail, but that the balance of the work shall be performed at cost to the contractor plus a reasonable percentage for profit on labor and material. Where but little machinery is required 10% to 15% may be sufficient for labor and materials, but where expensive machinery is re- quired or time is an important factor the percentage should be from 20% to 25%. It is the duty of the engineer to make preliminary examinations, soundings, drillings, etc., or other investigations as may be necessary to determine the amount and exact nature and character of the work. The result of the investigation should be given in detail for the information of all bidders and the engineer’s estimate should be made and the comparison of bids based upon this information. It may cost several hundred dollars to make such an examination and investigation but it should be made and the cost thereof paid by the state or county as the case may be. If a contractor makes the examination he adds the cost thereof to the contract price and the state pays for it in the end. As only one con- tractor can obtain the work it is not fair to ask each one of a dozen or more bidders to go to this expense, nor can it be exepcted that a contractor who has gone to such expense to give the information he obtains to his competitors. Stopping of Work An engineer should not have the right to stop work without allowing compensation to the contractor. Time is money. The contractor has his money, interest, insurance, plant and organized force and suspension means loss to him, both of service of plant and organization of force. There should be no power to stop work. except for valid cause, and some equitable means of allowing compensation for the cost of delay to the con- tractor. A contractor delayed by a delinquent or incompetent engineer or inspector, should have the time extended and be paid for the loss of time. Responsibility of Bidders A bidder should be required to submit a confidential statement in con- nection with his bid (preferable in a separate envelope) to show he has the necessary equipment or the necessary means and arrangements made to procure the equipment, experience and ability to do the work, a repu- tation for doing good work and on time, and has a working capital equal to 25% of the bid. The working capital should be in the form of cash, or an agreement with a responsible banking institution stating that they will advance and loan the contractor an amount equal to 25% of the bid. The statement should set forth in itemized form the contractor’s equipment, 40 resources, liabilities and references. Failure to submit or show such evi- dence should be absolute ground for rejection of the bid, specify the capital, experience and equipment required or necessary to have the work completed on time and in a satisfactory manner. It is just as logical to specify the aforesaid items as any other item in a specification. Payments of Estimates, Etc. The instant a payment of an estimate is deferred there is a breach of contract and the contractor should not be held to the agreement. Delay in payments are often very embarrassing to the contractor, places him in a bad light with his men, banker and creditors and often renders him unable to take advantage or trade discounts. The contractor should be allowed $25.00 per day for each and every day payment of an estimate is withheld and interest on all deferred payments. This amount is not exorbitant. Contracts should be specific when monthly and final pay- ments are to be made. Surety for Payment of Estimates The contractor is required to give bond for the faithful execution of the contract and it would seem only fair that the owner (City, County, or State) should give surety to the contrctor or make provision for pay- ment of all work performed, or material furnished according to terms of the contract, and to reimburse him in case of insufficient funds or an ille- gal contract. Where a contractor has performed work or furnished mate- rial in good faith according to the direction of those in authority or ac- cording to the opinion of the Attorney General or other legal adviser, we believe he should be paid for same, although the opinion should be later reversed by the court. Payments in such cases could be authorized and paid from a rotary fund derived from premium on bonds for contractors as mentioned elsewhere in this report. Contractors are not seeking generosity on the part of the State, but co-operation in obtaining and testing materials and in hastening the con- struction of the work and assurance of payment for the work so as to earn a profit. 41 TRAFFIC REGULATIONS Taxes on Heavy Trucks Careful observations show that heavy trucks, heavily loaded, are damaging our highways to a serious extent, and are the largest con- tributing factor in the cost and maintenance of our highways. The use of trucks is mostly a business or mercenary proposition on the part of the owners while the automobiles are used for both business and pleasure. The number of heavy trucks used are small compared with the number of automobiles used. One trip with a heavy truck with concentrated wheel loads will often do more damage than several hundred touring cars going over a road, therefore, the machines doing the most damage should be taxed the heaviest. Highways are built for convenience, business and pleasure. But why should all property be heavily taxed to construct and maintain a costly right of way and surface for companies engaged in transportation by trucks or to accommodate trucks carrying concentrated: wheel loads of any amount they choose to put on them? Companies engaged in other forms of transportation have to furnish and maintain their own right. of way and surface. It is decidedly unfair to levy a general property tax to provide for the additional cost necessary to meet extreme traffic con- ditions. Why should a man have to pay an exorbitant tax for a service which is not worth its cost to him and from which others derive far greater benefit at much less cost. The taxes on trucks should be in proportion to the damage and wear inflicted on our roads as compared with other vehicles. Suppose we construct heavier and wider highways at an excessive and almost prohibitive cost this year what is to prevent truck manufac- turers from designing and building trucks still wider, heavier and with greater carrying capacity next year, and so on, thus continually rendering our latest designs inadequate to meet the requirements of the truck manu- facturers and operators. When a railroad constructs a heavy road-bed to provide for heavier rolling stock, the additional cost thereof is paid by investors who expect to derive a direct revenue therefrom by a reduction in the cost of trans- portation. In highways the additional revenue and benefits derived by the people are very small compared with the extra cost of construction, maintenance, and interest charges necessary to provide for the transporta- tion of trucks with heavy concentrated wheel loads. For economy and safety and speed, wheel loads and width of trucks must be arbitrarily fixed at some definite, reasonable point. Otherwise we will be continually at sea as to how to design and for what to provide for the future. There is an economic limit (especially in our poorer and sparsely settled coun- 42 ties) where the public cannot afford and should not be expected to con- struct heavy foundations and expensive highways to accommodate a few private interests, representing a very small per cent of the traveling public. Solid vs. Pneumatic Tires The tax on solid tires should be considerable more than for pneumatic tires. The damages to the roads is three times greater for solid tires than for pneumatic tries, under the same load and similar conditions. The wear and damage to our highways by trucks with solid tires run- ning at high speed is many times more than the tax and revenue received therefrom or benefit derived by the state in any form. Solid tires gradually lose their resiliency from wear until they are no better than steel tires and may be even worse than steel tires’ due to the rims cutting into the surface. Solid tires which have become partially destroyed produce a hammer on the pavement at each revolution. Pneumatic tires do not lose their resi- liency with wear, and do not produce any hammer or so much vibration. Chains on solid tires damage a road surface similar to defective tires and should not be permitted on improved roads except on special occasions such as breaking a road through snow or on a grade. Auto Tax Recommendation We recommend a dual tax for all automobiles and trucks. tst. That all automobiles and trucks be taxed according to their weight plus their rated capacity in tons, as stamped on truck by manufacturer. 2nd. That a tax on the sale price of all gasoline used for transportation purposes be levied. Under the present system an owner who only drives a machine 500 miles per year is taxed just as much as an owner who drives a like ma- chine 30,000 miles per year. Under our present system of building roads it is the heavy trucks that do the most damage to our roads and should pay a considerable more tax in proportion. We recommend that a tax of Io per cent. be levied on the sale price of all gasoline purchased or used for transportation purposes :— That a tax of $15.00 per ton or fraction thereof be levied on both the weight of truck or trailer and rated carrying capacity in tons. We would collect approximately $30.00 on a I ton truck. $60.00 on a 2. ton truck. $90.00 on a 3 ton truck. $120.00 on a 4 ton truck. $150.00 on a 5 ton truck, etc. 43 Advantages of Dual Auto Tax The advantages of this system are: Ist. The heavier the truck and load the greater the damage to the roads consequently the higher the tax should be. and. By levying a tax of Io per cent. on sale price of all gasoline consumed by automobiles and trucks we take care of the following con- ditions :— (a) The more a machine is used the more is the wear on the roads, and the more gasoline will be consumed and consequently more tax will be and should be collected. (b) The heavier the machine and the heavier the load the greater the damage to the roads and the larger the quantity of gasoline con- sumed, consequently a greater tax will be collected. (c) The more the horse power the greater the speed of the auto- mobiles and the greater the damage to the roads and the more gaso- line will be used, consequently a greater tax will be paid. Note: To eliminate the tonnage tax entirely would be to eliminate a larger portion of the tax from heavy trucks which do the most damage to the roads. Trucks can be back geared so as to move a heavy load with small horse power. Distribution of Auto Taxes Distributing the auto taxes collected according to the mileage of roads in the state would give poorer counties and counties with a large mileage of roads additional revenue which is necessary if such counties are ever to have their roads improved. Trucks through smaller counties en route from one city to another damage the roads in said counties and derive scarcely and revenue therefrom. The portion of the auto funds alloted to the cities should be used first to construct, repair and maintain the streets connecting with the Main Market and Inter-County highways and, leading into and through the cities, so as to form a continuous line of improved highways and streets. ; Limiting Wheel Loads The use of motor trucks with reasonable carrying capacities are to be encouraged, but when truck manufacturers and operators wilfully tres- pass on the rights of the public in respect to the proper use of the public highways it is time to call a halt. ; The wheel loads should be limited regardless of the width of tire. In hard surface highways damaged by heavy loads we find cross-breaking and the surface crushed, cracked or damaged from one to two feet on each side of the wheel, as evidenced by depression made by the wheel. This result indicates that the damage would have been about the same had the tire been considerable wider. In gravel and macadam surfaces and 44 foundations there was more of a shearing effect near the edges of the tire, indicating the stresses were not distributed over so large an area of the surface and subgrade. ; We found a number of instances where the trucks were not only over-loaded but were not symmetrically loaded, the load being so placed that one rear wheel was carrying about two-thirds of the load In view of the foregoing facts and conditions it would appear that a wheel carrying a load of 7200 pounds, should be the maximum + wheel load with solid tires allowed to be transported over country high- ways — this is equivalent to a 12 ton truck with 60 per cent of weight on rear axle — and the width of tire should not be less than 12 inches. For less loads there should not be over 600 pounds, per lineal inch of width of tire. The width of tire should be determined by the portion thereof in contact with the pavement. If it is desired to haul a heavier load than above regulations would permit, we suggest that truck manufacturers follow the system followed by the railroads in the design of their locomotives and cars, that is build them longer (not wider and take care of the additional weight by the use of three or more axles and pairs of wheels. The wheels should be spaced not less than four feet on centers. Limiting Width of Trucks The width of trucks over all, including load, should be limited to 90 inches.. In exceptional cases a “special trip permit” might be author- ized by the County Surveyor. It requires an 18 foot pavement for two trucks go inches wide to pass with safety without reducing speed. Limiting Speed of Trucks Impact is an important factor in the destruction of our highways. The higher the speed the greater the impact. Solid tires produce heavy impact, especially when worn or damaged, hence the speed for trucks equipped with solid tires should be positively limited to ten miles per hour. All trucks should be designed to have as little weight below the springs as possible. Weight below the springs produces much greater impact than above the springs and for this reason trucks with solid tires should be quipped with chain drive. Trucks with pneumatic tires and having wheel loads of not over three and one-half tons should be permit- ted to run twenty-five miles per hour. The speed of trucks on bridges should be limited to five miles per hour. Penalty for Violating Traffic Laws Some companies furnish their drivers money to pay fines and con- tinue to overload their trucks — figuring it cheaper to pay fines than limit the loads. The penalty for violating the laws regulating the speed and loading of motor vehicles should be imprisonment in jail from 3 to 10 days for 45 first offense, 5 to 30 days for second offense and 30 to 100 days for each succeeding offense for the driver of the machine and the owner deprived of the use of his machine for a like period, and payment of all damages done to the road. We believe the aforesaid penalties are the only ones that will effectively reduce traffic violations to a minimum. . The actual weight of truck or trailer and the maximum weight of load (rated capacity of truck) permitted by manufacturers should be stamped and painted on the outside of the truck. No vehicle should be permitted by law to carry a load greater than specified by the manufacturer. Running Trucks in Fleets Running heavy trucks over roads close together or in fleets when the roadbed is soft has a tendency to puddle the subgrade, produce waves in the surface and cause the surface to crack, break and weave. They produce the same effect as too much rolling does on a soft or spongy sub- grade. Whenever there is likely to be a soft roadbed — the speed of trucks should be limited and the operation of trucks in fleets avoided as much as possible. Uniform Traffic Regulations The traffic rules and regulations should be made uniform and applic- able throughout the various: cities of the State. What is an offense in one city may be a law in another city. A motorist is continually at sea under present conditions — he is likely to be arrested for driving a certain way in one city and be arrested for not driving the same way in another city. Guide Posts and License Tags Printed signs or symbols should be placed at all road intersections showing what regulations of load and speed apply to each road. The signs should be plain and readily distinguishable by color or otherwise so as not to cause unnecessary delay in determining the conditions. We suggest a separate license tag of different design or color be issued for trucks of 3, 4, 5 ton capacity to enable any one to check at a glance the rated capacity of a truck going over any particular road. Tractors All new tractors, traction engines, etc., should be required to be equipped with smooth wheels, adjustable lugs or disappearing lugs or device of similar nature so as to avoid serious damage to our pavements. The same regulations as for trucks should govern loads allowable for tractors. Classification of Roads and Streets for Traffic It is financially impossible at present and will be impractical for many years to come to construct all county and township roads and city streets 46 to withstand heavy truck traffic. Many city streets, county and township roads are of light construction, and many of them con- structed in the future must be by necessity of light or cheap construc- tion. It is manifestly unfair to property owners in the poor sections of the cities and counties to have to build pavements for all classes of traffic, or to permit the destruction of pavements already built. Very few of our bridges have been designed, for heavy concentrated loads, and unless the loads are limited to certain highways, many of them will have’ to be rebuilt. Many bridges and culverts have already been damaged or destroyed by heavy trucks. A system of county and township highways and city streets should be laid out, classified, labeled and designated for certain classes of traffic. Permission might be temporarily granted by the County Surveyor in certain cases for heavier traffic than that designated for a particular highway. “The County Surveyor should be vested with authority to stop heavy traffic for a short period over any and all roads at certain seasons of the year, for instance, when the frost is going out of the ground. Enforcement of Traffic Laws The County Surveyor should be charged with the duty of enforcing the traffic laws on all state, county and township highways. And should have full power and authority to regulate the traffic, arrest any and all violators, and to appoint deputies with like power and authority. Con- stables, policemen, sheriffs and marshals should be clothed with like power and authority to make arrests. In attempting to arrest violators under present laws, many of them reach the county line just in time to escape arrest, and for that reason surveyor or other officers should have jurisdiction to make arrests in adjoining counties. The prosecuting attorneys should be charged with the duty of prosecuting all offenders of the traffic laws of the state. Traffic Commissioner The appointment of. a State Traffic Commissioner and several as- sistants with proper power and authority to enforce the laws and to co- operate with local city, county and township officials would be the best solution of the traffic problem. 47 HIGHWAY DESIGN Pavements should be designed according to the requirements of their use and to give reasonable service. There should be a good and definite purpose for every item entering into the design and construction of a road or pavement. Do not adhere too closely to “‘standards” though designed to reduce work and in a measure promote efficiency. They tend to eliminate freedom of thought, experiment, discovery and progress. There will usually be varying conditions and local influences which make it impossible to consistently follow any standard design or set of rules. General rules and rational formulae may be considered, but their use should be determined by reason and an observance of the peculiarities of the particular situation at hand. Highway design has ‘been based too much upon authority worship and not enough on scientific analysis.’ State Highway Plans The State Highway Plans are well inden but there has not been sufficient attention given to local requirements, soil and. drain- age conditions, materials, etc. The methods of design. are too gen- eral. They do not meet specific locations or conditions and often fail to provide for the use of local materials. Plans are frequently out of proportion where insufficient money is provided, viz.: high type pave- - ment, too much money expended on intermediate grades, not enough on limiting grades, too much on surface and not enough on drainage. Even where plenty of money has been available the results have‘ not always been as satisfactory as anticipated, or the cost would warrant. Most highways are gradually developed from a trail to a high class, modern highway, according as its use or prospective use warrants the expenditure for the various phases of the improvement. The develop- ment should progress in logical order as far as it is practical to do so. It may not be economy to attempt to build a road that will meet all the requirements of the future. In many instances there is not sufficient money available for the completion or permanent construction of all the desirable features at the time the improvement is to be made. Some features may have to be omitted and left to be taken care of by future development. It is therefore economy to construct first the fundamental elements which are the basis of later improvements and add thereto ‘in logical order other desirable features as future prosperity and thé avail- able funds will permit. This principle is too often neglected in the present design of our highways. Requirements in Highway Design Highway design varies from earth roads of the poor or sparsely settled districts to the hard surfaced pavements of densely populated 48 sections of our cities. Sparsely settled districts require the largest pos- sible mileage with limited funds. The densly populated or wealthy sections often require the most suitable pavement regardless of cost. To economically design pavements to meet the variable require- ments and complex conditions existing between the two extremes requires much study and investigation. A design for any locality depends upon the needs or prospective needs and resources of the local community, the relative importance the improvement bears to the general transportation — scheme of the country and outside assistance available on account of its general importance. In poorer districts a cheap type of construction must be adopted or a lot of financial assistance from outside sources received, to afford a continuous line of communication between various points. Scattered rural communities require road surfaces that are usable practically the entire year and sufficiently stable to provide for ordinary traffic. Densly populated disrticts and through commercial roads require heavy and dur- able construction sufficient for heavy traffic by trucks. Type of Pavement In selecting-a type of pavement it is necessary to take into consider- ation the factors which enter into an ideal pavement and the physical and mechanical agencies which tend to wear and disintegrate the pave- ment. The object of building a public highway is to provide a convenient and economical means of travel for persons and vehicles between various points ; to furnish a surface on which the force of traction will be reduced to a minimum and over which vehicles may pass with safety, convenience, expedition at all seasons of the year; to secure a covering that will pre- serve the natural soil from the effects of moisture and support the vehicles by distributing the weight over a larger area of the subgrade. A perfect highway should be as nearly dustless as possible, readily shed water, noiseless, durable, hard enough to prevent its heing cut up by heavily loaded wagons or trucks ,resilient enough to afford a good foot hold for and prevent injury to horses, moderate in first cost, easy and rapid to construct, repair and maintain, smooth but not slippery, easily cleaned, sanitary, agreeable to the eye, radiate but little heat, adapted to every grade, suitable to all classes of traffic and offer the least possible resistance to traction. It should be practically level and as straight as the countour of the country will permit and of proper width and cross section. To combine all of these qualifications so as to obtain the most suitable pavement for the desired purpose is very difficult. The mechanical and physical agencies which tend to wear, disrupt or destroy highways are the sun, wind, rain, moisture, changes in tempera- ture, frost, abrasion, impact, compression, shear and tension. 49 Some types may be cheaper than others, in first cost, but their life may be shorter or the annual expense of maintaining them, greater. In other types the first cost may be excessive, which renders the annual cost of maintenance high, due to the annual interest charge upon the difference in cost of the two types of pavements. This annual interest charge may be greater than the annual cost of the maintenance of the cheaper type. The engineer should determine, if possible, what type of pavement will be most economical in the long run. The truest econ- omy does not necessarily lie in the choice of the plan of least first cost, or even of greatest first cost. The element of time must enter into our calculation as well as the first cost of the pavement. In selecting a type of pavement the aim should be to give the public the maximum of benefit with the money available. The selection of a type or design of pave- ment should not be governed by commercial propaganda or theoretical prophecy. Disrupting Agencies In the design of the road the engineer should consider the kind, nature and action of the forces or elements which tend to disrupt or disintegrate the road surface and then select those materials and methods of construction consistent with economy and nature of the traffic, which will serve best to counteract those forces. The agencies which tend to disrupt, destroy or affect the life of highways are: Sun — Produces dust, shrinkage and expansion. Temperature Changes — Produce expansion, contraction, harden and soften bitumens, oils, etc. Frost — Cracks, raises, displaces, disintegrates, separates, etc. Wind — Displaces, dries up. Rain — Displaces, softens, expands. Traffic — Produces impact, abrasion, shear, compression, vibration, puddling, cracking, wear, crushing and tension. Impact — Result of hammer by horses hoofs. Result of hammer by uneven surface. Result of hammer by motion of wheels. Abrasion — Result of grinding and wear by tires. Result of grinding by weaving or shearing of surface. Shear — Result of friction of wheels on surface, Result of action of wheel on surface against subgrade. 50 Compression — Produces crushing by weight of load. Vibration — Produces fatigue, shattering, puddling of subgrade. Tension — Produced by drying out of concrete surfaces, etc. Saturation — Expands clays, makes clay fluid. Location The location of highways is an engineering problem and one which requires the exercise of seund judgment. The road should be located so © as to secure the best and most economical construction and for service to the traveling public. The location of highways has too often been a matter of political influence, selfish motives, catering to the whims of ~ constituents or for only present convenience and with little or no thought of the future. ; The location of a road not only includes the right of way on which the road is to be built but the grade lines which govern the grades, the excavation, the embankment and the drainage scheme of the roadway. These are considered the permanent features of a road but they are permanent only in so far-as they are properly and scientifically done. The drainage of a road depends largely upon its location. A properly located road will be a well drained road after construction and an asset to the community through which it passes. . To the general public the surface is usually considered the most important feature of a road. Upon the location of a road depends the durability of its surface, the distance traveled, the speed traveled, the maximum loads that can be hauled, the drainage, the ruling grades and the cost of construction and maintenance. There should be more emphasis on location than is customary. The sooner roads are properly located the better, as land values are con- tinually increasing and structures of a more or less permanent nature, are being erected from time to time, which makes changes in road loca- tion expensive. All locations and grading should be properly done at first as it is expensive to relocate or grade a road after the right of way has been procured and surfacing material has been placed thereon. In locating a road the engineer should strive to obtain the most eco- nomical and equitable adjustment of each without sacrificing any other to any great extent. There are limits beyond which none should be sacri- ficed. . The ideal alignment is a level grade and a straight line but this is usually impossible except for short distances. Straight lines and level grades often make drainage difficult and grading expensive, if a road is longer than necessary it adds useless cost to construction and maintenance, | and to the traveling public. The best location is a line straight in general direction free from steep grades or sharp curves located on solid ground, which has easy drainage and serves the largest number of people. High- 51 way location resolves itself into a problem of an economic compromise of alignment, grade and cost. Location is the only absolute permanent detail of highway construction and should approach the ideal as closely as possible. Curves The cost of a curve to each vehicle is the amount of fuel necessary to regain the original momentum lost in slowing up for the curve, plus the loss of time in accomplishing the same purpose. The fuel and time lost could readily be determined for various vehicles on the different degrees of curvature and rates of speed and some one should be assigned to the duty of making the aforesaid determination. From a census of the traffic the saving in fuel and time can be determined. The value of the fuel and time saved would be the interest on the capital which we would be warranted to expend in straightening the curve, this does not take into consideration the loss due to accidents on dangerous curves. Short, sharp, or reverse curves or corners are dangerous and should be avoided where possible. Avoid square corners by the use of curves and diagonals. The amount saved in construction and maintenance will usually more than pay for the land the distance will be’ shortened thus making a saving to the traveling public. At cross roads curves should be made at each corner conforming to a 20 foot radius. Curves should be not sharper than 80 degrees and the outside of the surface should be super elevated. Curves sharper than 20 degrees are dangerous and super elevating the outside of the surface makes the curve look like a race track thus inviting disaster besides being an inconvenience to slow traffic. All curves on grades should be compensated so as to provide more safety and to give a more artistic effect. Compensate 1% for each 5 degree of curvature in excess of 10 degrees until 2% is reached. Vertical curves should be placed wherever there is a break in the grade line. Clear Sight Distance Clear sight distance is the distance a person driving an automobile on a vertical or horizontal curve can see another automobile approaching. The “clear sight distance” depends upon the width of road, surface, berns, ditches and position of the automobile on the road. A 20 degree curve gives about 200 feet “clear sight distance” on a 26 ft. radius and a 9 degree verticle curve should be the limiting verticle curve. This will prevent excessive wear and will give sufficient “clear sight distance”’. For a speed of 30 miles per hour it will require about roo feet for an automobile to stop with convenience and safety on a dry or rough surface, 52 Points for Consideration in Highway Location General Location: (1) Selection of best general route (2) Best location for future development (3) Least rise and fall (4) Least length (5) Least cost (6) Least ice and snow Engineering Location: (1) Best engineering location (2) Reasonable grades (3) Character of excavation (4) Character of soil and sub-soil (5) Drainage problems (6) Natural restrictions (7) Artificial restrictions (8) Exposure Grade: (1) Maximum grade (2) Present requirements (3) Future requirements (4) Intermediate grades (5) Economical grades Allignment: (1) Dangerous curves (2) Dangerous railroad crossings (3) Future requirements Width of Roadway: (1) Widen at curves (2) Safe for travel (3) Sufficient for travel (4) Avoid dangerous ditches (5) Convenient for travel (6) Future requirements (7) Clearing to admit the sun Drainage Structures: (1) Proper location - (2) Drainage of road bed (3) Ditches (4) Culverts (5) Bridges (6) Permanency of construction Safety: (1) (2) (3) (4) (5) (6) (7) (8) 53 Dangerous ditches Dangerous slopes Dangerous curves (vertical and horizontal) Dangerous railroad crossing Too light bridge construction Narrow roadway Narrow pavement Steep grades Right of Way: (1) (2) Sufficient for present use Provision for future use Future Improvements: Provision for widening roadway without losing benefit previous work Provision for raising grade at low points Provision for lowering grade at high points Provision for widening paved surface Provision for better drainage Provision for sidewalks Provision for planting trees Provision for city allotments. 54 GRADES Steep grades increase the cost of maintenance and transportation. They limit the loads that can be hauled by horses and the speed of both horse and motor traffic, which reduces the value of a road. The effect of grades is the permanent and effective limitation of traffic. They may ~ be reduced or avoided by a proper location and by excavation and em- bankment. , Location of Grades By locating a road around a hill to grades may be avoided or re- duced without materially increasing the distance. It is a waste of money to reduce a three per cent grade to a two per cent grade, where the ruling grade is four or five per cent. It is usually good practice to economize on grades less than three per cent and on unimportant sections of a road, and expend this. money in reducing the ruling grades. A common error is in making the cuts and fills balance. It is often cheaper to waste excess dirt or borrow where there is a shortage of material. A rolling grade is usually an economical design and one inducive to easy drainage. Long straight grades are seldom required. ; In side-hill work it is often better to waste material and locate the road entirely in a cut where there is danger of settling or sliding or where a stream runs along the base of the side hill. Side-hill slopes should never exceed 20% unless made from solid rock excavation en- closed at the base. Relation of Grades to Horse Drawn Traffic A horse can usually draw (for a short distance) as much on a four or five per cent grade as he can continuously on the level. A grade should not be steeper than a horse can descened in a trot or which a team can safely descend with a load in ten hours. Five per cent is the maximum grade that can be descended with safety by a trotting team without the use of brakes. A three per cent grade is the maximum grade on which a vehicle will remain stationary without the use of brakes. Ona hard and reasonably smooth road a team can haul 34 tons up a 5% grade. Assuming the weight of wagon to be ? tons, the net load is equivalent to over 83 bushels of wheat, 50 bales of hay or straw, 83 bushels of potatoes, 142 bushels of ear corn, or 156 busheis of oats. These quantities exceed in bulk the carrying capacity of the average wagon. For team hauling a 5% grade should be the maximum grade considered for economy. 55 A load that two horses can haul with economy over a comparatively level road -will require for: A 23% grade— 2 horses. A 6% grade—5 horses A 4% 6é Pasen 8 “ec aay 7% 66 SU. 6 “ce A 5% (v3 ens 4 “cc JN 83% ce bot ff 6c Assume cost of teams at $7.50 per day: An average team will travel 12 miles (round trip) per day An average team will haul 33 tons one way, return trip empty. Assume weight of wagon to be @ tons Assume net weight of load to be 23 tons 24 tons X 12 = 30 ton miles $7.50 + 30 — 25 cents, cost per ton mile for team hauling. Figuring transportation on the basis of 25c per ton mile (level to 244% grade) and an average of 1000 tons transported per yean over a road, the approximate cost will be for a: Level to a 24% grade, 2 horses —cost 25 c a ton mile saat aoe tS Din, aie 5, DPR CKa ok pete $e EE BY eS Be rt ag eit eae ee Meee Lone | fa: Oe on peesoto), COAG ey Bg ee rig es re a ako G Rpts tore 1G BAT 5 Oe ace” Wire PRI = Ee ae The difference between the operating cost of a 23% grade ane a 4% grade— $0. 374 — $0.25 — $0. 124 per ton mile 24% 59a) i 0 BO as 0 Oe O05 24%. Bel “690.20. od 0624 — OL 25s2 M8Th- fs r 23% “ Dect EO they. Abece: Ah a e ARI = AE s Pe erate ad Oeoe es OB TA 0265 = 50. Hee Sin a Oe on ayant: vik 0 Oar a OOO Toa oe a a Pm ae AE oy ah eee Ee) ee ee eee tee es Oi POR ol te ee Te 0 er ST Sy Sees ere iii Pad PEO oe OO Gee BO Fe tee The difference in the annual cost of operation per mile between a 24% erade aud a 4% grade ~~ 90. 124 & 1000 tons thd scone at ae. 00 ° 22% 5% — 0.25 DG. ahs ‘ = 250.00 23% =.“ PREIS 5135 Conan A Ses le Sa ‘ 4 = 375.00 22% ==“ Nai” eR tek pee aU | Rb dean ye = 500.00 23% 8“ Cots DOR Tp ete (OOda Se ‘3 . = 625.00 5% eg Cae earn TPN De? ty eke " ut = 125.00 i Be TUR? STs et me), OB SRS . s = 250.00 ey el (ER TOL en) hae OBIS Ko a ‘ = 375.00 Be re nape il vs 0.056. 8 oie fst 500.00 56 The difference in the annual cost of operation per station of 100 feet between a 24% grade and a 4% erage 00 + 52.8 = $2.36 24% > * OVO ale 250500 “52-8 == 4273 22% = Feo Tae 6) Og Soot errs ease yA) aie co ea TF PP OL), aed BASS ef Toman ate OR OU ienams oe Ore OLS Bao ~ ™ SOE ORG AE en 625 0M Do SisaalL ERS BIG 3. 4 OI, oe om OD nm toes =e GO omen EGG EP es SOOO: Dae et eS By Yousanr ss FETE OL ea OT ROE RENO = eey el) Vonme bee LO GGy te ait ee wR OOns Bnei Sa —eeOAG Figuring interest at 5% and using the above figures as a basis, it will usually be economy to expend $2,386 5% = $47.34 tor reducing oan m0 * of 4% grade tg 23% grade 4.73 +5% = 94.68 “ 5% 1965 TA0+ 5% = 142,02 “ Nr UNS Caeebsmpe ua), Os 9,46 5% = 18936 * >“ MMe es aden OS O28, 11.838 5% = 236.70 “ . “ eRe Ss Pca ea eet ie 2.36+-5% = 47,85 * Pee eee (uaa ae a 2.36 5% = 94.68“ are ed cei Mls Maoh uel ES 710.4-5% = 142,02 # jiestematna! «aia tere og 9.46+5% = 189.36 “ .“ aaNet hae Vly craubate aah p80 1000 tons was used as a basis of the annual tonnage transported in order that the expenditure justified for any other road could be readily calculated by taking a census thereof. Allowance should be made for a reasonable increase in tonnage due to the improvement of the road. There is a greater loss of potential energy with horse-drawn traffic than with motor traffic as there is but little kinetic energy at the foot of the grades on account of necessary reduction of speed by the use of brakes on grades above 3 per cent. The destructive effect of storm water is four times greater on a 5% grade and nine times greater on a 10% grade than on a practically level grade. The per cent of horse drawn traffic varies from about 5% of the total traffic on some of the main market roads to about 80% on some of the inter-county roads in the hilly counties. Relation of Grades to Motor Traffic On account of the public receiving no direct or tangible revenue from money expended in highway construction, there has not been suffi- cient time given to comparing operating costs with construction costs. The public is willing to pay a reasonable amount for improving tran-porta_ tion conditions but is not willing to expend large sums in the reduction of grades which will benefit only a small percent of the traveling public, and from whom there seems to be no way to collect a revenue to pay for the addtional construction necessary to further reduce the grades. 57 The relation of motor traffic to grades is different from horse-drawn traffic in three essential particulars: tst Motors are provided with shifting gears for operation on grades or on bad roads which permits of using the same power unit without reducing the load. 2d The load including the power unit can coast down the grade with but little loss of energy or fuel. 3d The speed down heavy grades without the use of brakes is relatively faster with motor than horse traffic, consequently less energy is lost with motor traffic. There is so much variation in the nature, class and amount of highway motor traffic and the weight, power, gear ratios, capacity and efficiency in the operation of motor vehicles that the analysis of high- way locations and establishment of grades thereon can not be made with the same refinement as applied to railroad locations. Most pleasure cars and trucks can ascend or safely deveond aah per cent grade. The per cent of grade at which different cars and trucks are required to shift gears varies considerably. It would simplify highway design if all manufacturers of cars and trucks would design their power units and gear ratios so that shifting from high to intermediate gear, would not be required up to and in- cluding a 5 per cent grade, and from an intermediate to low gear up to and including an 8 per cent grade for trucks and from high to inter- mediate gear up to and including an 8 per cent grade for pleasure cars. Some uniform method of design of gear ratios should be adopted in order that grades could be established with some degree of economy for motor operation. As far as convenience in “shifting gears” and “time” are concerned, it is apparent that if a 5 per cent grade cannot be obtained there is no advantage in making heavy expenditures in reducing a 7 per cent grade to a 6 per cent grade, etc. It is fair to assume that the fuel consumption is proportional to the energy expended. The work required to haul a load between two points equals the “grade resistance by the rise in feet” plus the “rolling re- sistance by the distance in feet.” Illustration Rolling and Grade Grade Resistance Rolling Resistance Resistance Level 00 Ibs. per ton of load al Ibs. per ton of load 40 Ibs. 1% PAN) “ “ce “c “ce “ “c a “ “ “ 60 4“ 2% 40 “cc “ “cc “ “i “ce “e ics “ “e ce 80 6e 3% 50 “ec “cr “6 6c 6c d “ce “é “ “ itd “ 100 “ 4% 80 “cc ins “ee “cc “ “cc “ “ac “c ce “ce 120 4a 5% 100 “ <6 7 6 “ec ‘6 “¢ “ “ ¢ ‘ 140 4 58 Assume weight of vehicle and load equal to 10 tons distance equal to 8,000 feet a fixed rise of 60 feet distance between terminals on the different grades to be equal “ce “ee Total oe >! Soe EDS, Length Length Ft. lbs. Ft. Ibs. Energy oP tn ae Energy Energy for Grade grade. level on grade on level 8,000 ft. PP SR ea kde epee als t? 6000? 2,000° 360,000 80,000 440 ,000 Bei ta ies ae was Baie 3,000’ 5,000’ 240, 000 200,000 440,000 oS ek CMOS AAS RTS ae ree 2,000’ 6,000’ 200,000 240 , 000 400,000 2 YAS oo teen tee aid 1,500’ 6,500’ 180,000 260,000 440,000 DUD: eis | eae ea 1,200’ 6,800’ 168 ,000 272,000 440 ,000 Therefore the fuel consumption does not depend upon the rate of grade for a “fixed rise or fall” for an equal distance between two points, but depends upon the “distance” with a fixed rise and fall be- tween the points. It is essential however to eliminate unnecessary rise and fall between two points providing the distance is not materially increased. Value of Reducing Total Rise Assuming no air, rolling or frictional resistance or loss of energy due to the application of brakes or the engine running idly while coast- ing, the work required to haul a load to the summit of a grade equals the potential energy at the summit which equals the kinetic energy of the truck (due to coasting) at the foot of a grade of equal rise; if the truck is not stopped at the foot of the grade but continues coasting there is no loss of energy and consequently no advantage in reducing the grade. If a grade is so steep or so long that it is necessary to apply brakes to descend with safety or to limit the speed, there is a loss of energy and every foot of rise eliminated will be a direct saving, The rolling and frictional resistance of a truck about equals the grade resistance of a 3 per cent grade for the average road surface. It will be observed that on grades of less than 3 per cent no shifting of gears is required and there is little loss of energy due to the engine run- ning idly or by the application of brakes, consequently there is less loss of potential energy on light than on heavy grades. Most cars will ascend or descend a.5 per ceftgrade without shifting gears, applying brakes or materially reducing the speed, therefore, it is evident that there is little advantage in making heavy expenditures in reducing grades less than 5 per cent or in reducing or eliminating light intermediate grades. The time factor is almost negligible except on long grades, 59 The cost of hauling per ton mile is greater on short hauls than on long hauls on account of the loss of time loading and unloading. On account of the lack of organization and co-operation in transportation it is necessary to figure a truck loaded but one way and returning empty. The speed at which a truck can descend a grade with safety depends upon the alignment, condition of surface, mechanical condition of the truck, length of grade and experience of the driver. For commercial roads assume speed of truck: In high gear pneumatic tires at 25 miles per hour In high gear solid tires at 12 miles per hour In intermediate gear solid or pneumatic tires at 7 miles per hour In low gear solid or pneumatic tires at 3 miles per hour Rolling plus frictional resistance equals grade resistance of 3% grade V=velocity g=—acceleration = 32 V= V2.2 h sin.o = V2 gh per sec. SaVaSogo Th == 8Vh per sec. 5.5V h miles. per hour TABLE A Velocity in miles per hour due to gravity Grade S=length at grade \ \ 5 | 200 300 400 500 | 600 700 800 | 900 | 100041100 | 1200 — > —) DONMNMRRrR A DD tO OTF © (aoe Ye oan) ae Fen) DODO DO Rk * NR ADO Or WHEW _ Dor WS Crors o@) a> VRS —— ao BWDRr ONO ore COO Oro oO DR Hee CONC WrRANOS oe RORONS | DODO DOR He Cr OMwocd do Www So ob Or | I ) The loss of energy descending a grade depends upon the speed a truck approaches the grade, length of grade and speed allowable on the grade. If a truck approaches a descending grade of 3% at full speed the truck will coast down the grade with but little reduction or accellera- tion of speed or loss of enrgy except the motor running idly. If ap- proaching grade at less than full speed the motor can accellerate the speed to that of safety in descent. With an equal tonnage in each direc- tion, the chief loss of energy due to a grade occurs in descending the grade on account of the necessary limitation of speed by the use of brakes in order to descend with safety and in stopping at the foot of the grade when required. aig contac Speed approaching de- scending grade Max., speed, solid tires 12 miles per hour Ist gear, 3 mi. per hour,, 2nd gear, 7 mi. per hour 3rd gear, 12 mi, per hour. Max. speed, pneumatic tires, 25 mi. per hour 60 TABLE B Length of grade on which there is no loss of energy but beyond which loss of energy occurs by the use of the brakes. 3% 4% | 5% | 6% . 7% | 8% | 9% | 10% Any 270 | 185 90 67 Any 00; 00] 00 00 00; 00 vA | Any B82) ALA Ope sOLes Migs aioe aay 00 | Ist gear, 3 mi. per hour. 2nd gear, 7 mi. per hour 3rd gear, 12 mi. per hour 4th gear, 25 mi. per hour Any | 1600] 800; 536/ 402 | 822 | 268] 230 Any 1080 | 540; 360 | 270} 216 | 180 | 155 Any 063 | 281 | 187} 141] 118 94 80 Any 000 | 000} 000} 000 | 000; 000 | 000 } The chief loss of time occurs in ascending a grade due to the necessary use of low gears to overcome the grade resistance. Loss of time in descending a grade occurs until the maximum speed is reached. LADLE Loss of energy per ton in thousands of ft. lbs. due to brakes Max. speed Approach- 100 No accelleration,except gravity. Length of descending grade 0. 5% 112 3 mi. | 0. 5% |12 7 mi. | 2. 5% |12 12 mi. | 4. 5% |25 3 mi. | 0. 5% |25 7 mic | 0. 5% |25 12 mi.| 0. 5% [2h 25 mi. | 4. 8% 112 3 mi. | 4 8% |12 7 mi. | 8 8% |12 12 mi. | 10. 8% |25 3 mi. | 0. 8% |25 7 mi. | 0 8% 12 mi. | 0 8% 25 mi. | 10. 10% |12 3 mi. | 9. 10% 7 mi. | 12. 10% 12 mi. | 14. 10% |25 3 mi. | 00. 10% 7 mi. | 00. 10% 12 mi. | 2. 4, puch i) x no Or = — SBSSOMHSSSSOSOUMSSOSSOROSO. MDWOSAHSCSUSCSUUASHORSE SEL OO 200 | 300 | 400 | 500 | 600 | 700 | 800 900 | 1000 0.017 050). .0701 =. 0. OF 0.0.00 0.0 0.0; 0 2.6] 6.6} 10.6) 14.6) 18.6) 22.6; 26.6) 30.6} 34 6.4) 10.4) 14.4) 14.4) 18.4] 22.4) 26.4); 30.4) 34 8.0; 12.0; 16.0! 20.0) 24.0) 28.0) 32.0) 36.0; 40. 0.0; 0:0) 0:0) 0.0). 0.0) 0.0 0.0 4.0, 8. 0.0) 0.0) 0.0) 2.4) 6.4) 10.4, 14.4 apt: 0.0; 0.8) 4.8) 9.8) 12.8] 16.8) § 20.8) 24.8) 28 8.0} 12.0) 16.0} 20.0) 24.0) .28.0) 32.0; 36.0) 40 14.5) 24.5) 34.5) 44.5) 54.5] 64.5) 74.5) 84.5) 94 18.5] 28.5) 38.5) 48.5} 58.5] 68.5) 78.5) 88.5] 98 20.0; 30.0) 40.0) 50.0) 60.0) 70.0; 80.0} 90.0; 100 0.0; 0.0; 8.0} 18.0} 28.0) 38.0) 48.0) 58.0) 68 0.0) 8.5) 18.5} 28.5) 38.5) 48.5) 58.5} 68.5; 78 8.5) 18.5) 28.5) 38.5) 48.5) 58.5) — 68.5) 78.5] 885 20.0; 30.0) 40.0) 50.0} 60.0; 70.0; 80.0} ..90.0, 100 23.1) 37.1) 51.1} 76.7} 79.1) 93.1} 107.0) 121.1) 185 26.6) 40.6} 54.6) 68.6) 82.6; 96.6). 110.6} 124.6, 138 28.0} 42.0) 56.0) 70.0) 84.0) 98.0} 112.0; 93,8) 140 00.0} 9.8) 23.8) 37.8) 51.8] 65.8) 79.8) 93.8] 107 6,3} 20.3} 34,3) 48.3) 63.3) 76.3} 90.3) 114.3] 118 16.8} 30.8) 44.8) 58.8} 72.8] 86.8) 100.8) 114.8) 128 28 ° 42.0) 56.0 rt 84.0; 98.0} 112 0; 126.0) 140.0 61 The foregoing table shows that it may frequently be economy to build heavier and wider pavements on grades and approaches to ascend- ing grades and to use pneumatic tires so as to permit greater speed with safety on grades. Assume cost of operating a 5 ton truck at 5c per min. Assume cost of fuel for 5 ton truck 2c per min., total 7c. Assume cost of operating a 5 ton truck at 25c per mile. Assume cost of fuel for 5 ton truck at toc per mile, total 35c. Rolling resistance equals 4o Ibs. per ton mile. 40 X 5280 equals 1056000 ft. Ibs per ton. 0.56 + 1056 = .00035 per 1000 ft. Ibs. per ton. TABLE D Loss in money per 100 tons due to brakeing on grades es : © Lo Length of descending grade rom es ° ] cs ae = pe 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 1000 12 to 3 to 24 mi.| 25 mi. | 0.00! 0.00} 0.00) 0.00; 0.00) 0.00! 0.00] 0.00] 0.00) 0.00 12 mi.| 3 mi. | 0.00! 0.09] 0.23] 0.37] 0.51] 0.65] 0.79] 0.93 1.07| 1.21 12 mi.| 7 mi. | 0.08] 0.22! 0.36! 0.50] 0.64| 0.78! 0.92) 1.06] 1.20! 1.34 12 mi.| 12 mi. | 0.14] 0.28] 0.42] 0.56! 0.70] 1.84) 0.98) 1.12) 1.26] 1.40 25 mij 3 mi. | 0.00] 0.00| 0.00] 0.00) 0.00] 0.00] 0.00] 0.00] 0.14] 0.28 25 mi.| 7 mi. | 0.00! 0.00] 0.00] 0.00] 0.00] 0.08] 0.22! 0.36 0.50) 0.64 25 mi.| 12 mi. | 0.00| 0.00] 0.03} 0.16! 0.30] 0.44) 0.58) 0.72) 0.86] 1.00 25 mij 25 mi. | 0.14] 0.28] 0.42] 0.56) 0.70) 0.84) 0.98] 1.12! 1.26} 1.40 P2mit.) 3 mi. | 0.15) 0.50) -.85)-1..20/ 1.55! 1.901" 2.95)5:2.60) 995886 12 mi! 7 mi. | 0.29} 0.64) .99| 1.34) 1.69} 2.041 2.39! 2.74! 3.09! 3.44 12 mi.| 12 mi. | 0.35) .70} 1.05] 1.40! 1.75} 2.10] 2.45) 2.80] 3.15) 3.50 125 mi.| 3 mi. | 0.00! 0.00] 0.00] 0.28] 0.63} 0.93] 1.33! 1.68] 2.03] 2.38 25 mi.| 7 mi. | 0.00! 0.00] 0.29] 0.64] 0.99! 1.34] 1.69] 2.04 2.39! 2.74 25 mi.| 12 mi. | 0.00] 0.29] 0.64] 0.99] 1.34) 1.69] 2.04) 92.39] 2.74] 3.09 25 mi.| 25 mi. | 0.35) 0.70] 1.05] 1.40) 1.75] 2.10] 2.45) 3.80! 3.75! 3.50 12 mi| 3 mi. | 0.31] 0.80) 1.29] 1.78] 2.27] 2.76] 3.25] 3.74] 4.23] 4.62 12 mi.} 7 mi. | 0.44! 0.93) 1.42] 1.91] 2.40) 2.99] 3.82) 3.87; 4.36) 4.85 12 mi.) 12 mi. | 0.49] 0.98] 1.47/ 1.76; 2.45] 2.94 3.43] 3.921 4.41! 4.90 25 mi.| 3 mi. | 0.00/ 0.00] 0.34] 0.83) 1.32] 1.81] 2.30] 1.79) 3.28] 3-77 29 mi 7 mi. | 0.00) 0.22] 0.71] 1.20] 1.69} 2.18! .2.67] 3.16] 3.65] 4.14 25 mi.| 12 mi. | 0.10) 0.59] 1.08] 1.57] 2.06] 2.55) 3.04| 3.53] 4.09] 4.51 25 mi.| 25 mi.-| 0.49] 0.98] 1.47| 1.76; 2.45] 2.89] 3.431 3.92] 4.41] 4.90 Assume speed of truck solid tires 1st gear 250 feet per min. Assume speed of truck solid tires 2d gear 500 feet per min. Assume speed of truck solid tires 3d, gear 1000 feet per min. Assume speed of truck pneumatic tires 4th gear 2000 feet per min. 62 | TABLE E Loss of time in minutes due to ascending a grade s Solid ; 2 tires Length of grade Qa : ‘ ecb per | Pe A Ss |e ‘S 100 | 200 | 300 | 400 | 500 | 600 a 800 | 900 |1000 8to 12% {125}. 3.) 2st A028 Oe 6s 20) 98 Tee | stele Seti Oa = ee ada ale) Bto. 8%" | 12 6a), Sindy a= OLD Oe FOS nO. 40 saat tyeal srg antes) es ex en exon (eat) O8to= 5902S 12 123) 8 rd--1'0.05)2050517 020210202020 0202008 020s S00 0200 Pneumatic tires Soto aos 2b. aon et .80) 70} 1.05) 1.40) 1.75) 2.10) 2-45) 2.80) 3. 1513.50 tos 8001 | 20 dle 1a end. S15|- 380k 245l>-. 60S 275)|> S90 051 e201 sail 50 Oto 7025 12 eord SOB LGR lee 0s BAS crepneh (eee oy et 0) eed peers 0 to 3% | 25 125 | 4th ses! 0.00} 0.00} 0.00} 0.00) 0.00) 0.00} 0.00] 0.00/0.00 Solid : 3 tires é Loss of money in cents at 7c per minute ou vo = 4 2 = a ee | i a Was = o 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 |1000 O al|n O | 8 to 12%/} 12} 31] Ast | 2.1 | 42°] 6.3 | 8.4 110.5 112.614.7168 |18:9 |21-0 5 to. 8% | 12 | 6°] 2nd TV Lae Sal 2 8c) BiG 22) Ae cela ea ne 0 to 5% | 12/12] 3rd | 0.0] 0.0 | 0.0] 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 Pneumatic tires 8 to 12%: | 25 |-3 | Ist | 2.45) 4.90) 7.35) 9.80/12.25/14.7 |17.15)19.6 122.05/24.5 5 to 8% | 25] 6] 2nd | 1.05] 2.10) 3.15) 4.20] 5.25! 6.30) 7.35) 8.40) 9.45)10.5 0 to 5% | 25.| 12 | 3rd .35| 70) 1.05) 1.40) 1.75) 2.10|-2.45| 2.80] 3.15} 3.5 0 to 3% | 25 | 25 | 4th | 0.00, 0.00} 0.00; 0.00} 0.00] 0.00) 0.00) 0.00} 0.00). 0.0 The driver’s time and the time of ascent on a grade are practically the same for a one, two, three, four, five, etc., ton truck. The fuel cost is porportioned to the weight transported including the weight of trucks. The fuel cost is a small part of the operating cost of a truck. In figuring the loss of time per ton it is necessary to consider the weight and max. capacity of the truck permitted to be used. 63 (Ss D Fic. I In going from B to C there would be a loss of energy but not of fuel in descending a grade on grades above 3% due to the necessary application of brakes to offset the accelleration due to gravity as a truck would likely approach B from A at the maximum allowable speed. In going from C to B there would be a loss of both time and fuel on grades above 3 to 5%. There would be no saving of energy or fuel in reducing the per cent of grade but there would be a saving of time in reducing the grade to correspond to the gear ratios of the average truck. If a driver slowed up in approaching B from A and coasted down the grade there would be a slight saving of fuel with a consequent loss of time but as time is the most expensive factor this would not be economy. . Were the tonnage all in one direction the grade would be an ad- vantage or disadvantage as the case may be. A Be. 2» D Soe ee Bice Ly A B D E CO Fic. III In going from B to C or from D to C, Fig. IJ and III, there is a loss of energy but not of fuel.- In going from C to B or from C to D, there is a loss of both time and fuel. If one or both grades were re- duced so as to raise the point C there would be a saving of both time, fuel and energy. If a truck could coast down B to C safely and not ex- ceed the max. speed allowable there would be no loss of time, fuel or energy (except in going from F to B), but this would seldom be practical, | 64 HuGreva In going from B to D or from D to B, Fig. IV, there is a loss of time ascending the grade and may be a loss of energy descending the grade, depending upon the speed allowable and length of grade. There is a slight loss of time descending the grade until the truck arrives at maximum allowable speed. There will usually be a saving of time and fuel in reducing the grade and in lowering the point C. The expenditure warranted for any particular grade can be ap- proximated by taking a census of the probable traffic and calculating the cost in time and fuel from the foregoing tables. For a variety of traffic the fuel expended on a grade is about proportional to the total weight of vehicle and load transported. The time factor can be com- puted from the capacity, weight, power and gear ratios of the average machine of a particular class as a one, two, five ton truck, touring Car, etc, 65 DRAINAGE Object The object of any drainage system should be to prevent saturation of the roadbed and subgrade and to maintain, as far as possible, at all times a dry subgrade for a depth of at least two feet or more. The drier the subgrade the less the heaving and cracking by frost and the less foundation material required. The most essential feature in the construction and maintenance of public highways of any type, is to provide ample and sufficient drainage of the roadbed and wearing surface at all points and in no place leave it possible for water to collect in pools on the road surface or along the sides of the roadbed. Drainage intercepts the water which would other- wise reach the road or roadbed and removes the water which might accumulate on the surface or sides of the road. A hard surface of any type requires a compact roadbed thoroughly drained. A good road cannot be maintained without a good foundation, and an undrained roadbed is a poor foundation. It is of small im- portance what sort of pavement is used unless you have a good well- drained roadbed. Adequate and effective drainage must be provided at all times. If proper drainage is not provided the roadbed will become soft and yielding by the capilary action of the soil which draws water from the surface and sides of the road and underground sources, and it will. be. difficult to construct or maintain the road surface. Better have a poor pavement on a well-drained roadbed than a good pavement on a poorly drained roadbed. Water should never be permitted to stand on the surface or along the sides of the road or to penetrate the roadbed. If an earth road, it will soften the surface, produce ruts, holes and mud, thus impeding the traffic if not obstructing it altogether. If macadam, it will soften the foundation so that the stones will be forced down into it by the wheels of passing vehicles thus causing ruts and holes to develop in the surface of the macadam. In freezing, it expands and heaves the stone, destroys the bond, and causes the larger fragments of stone to be displaced. As a result the material in the subgrade is forced into the interstices and in the spring the macadam will be found to be rough, wavy and weakened or broken up. If a brick or concrete road, the freezing will cause cracks, displace- ment and disintegration of the road surface, on account of the unequal distribution of moisture in the roadbed, and the intermittent and un equal freezing and thawing of the same. The composition and nature of the soil, the grade and alignment of the road, the climatic differences of temperature, moisture, wind, and 66 contour of the surrounding country, determine the method and amount of drainage required. Soils The kind and nature of the soil is such an important factor in de- termining the manner and amount of drainage necessary and the char- acter of foundation required, that a brief discussion of soils and their relation to highway design and construction is very essential. . The sandy, loamy and silicous soils are not difficult to drain, but aggillaceous soils and marls retain the water and are easily affected by freezing and thawing. The chief characteristics of soils affecting highway construction are capillarity, permeability, density and stability. Soils are usually com- posed of sand, gravel, clay and various mixtures of these soils with calcium carbonate, decayed vegetable matter, etc. Capillarity The more soil is susceptible to capillary attraction the deeper the ditches and subdrains should be to prevent the water from rising or flowing laterally and saturating the roadbed, and to keep the subgrade dry for at least two feet, depending upon the nature of the traffic. Water rises vertically in one day, due to capillary action, from 8 to 9 inches in sand and to about 20 inches for some variety of loams and in 3 to 10 days may rise about twice the above heights. Water will flow horizontally due to capillarity from 5 to 30 feet in 24 hours. Where water is present continually and in quantities, the effect of capillarity may be about four times greater. The per cent of moisture in some soils is practically uniform at different depths. Water stand- ing or flowing periodically along a roadbed, even for a short time, may be detrimental to the life of the road surface. From the above data the necessity for deeper ditches and sub- drains is very apparent. In this climate we frequently have several days of wet weather or melting snow, and it is very evident that with some soils and a road constructed and maintained according to the present practices of the highway department we would have at times a saturated subgrade and roadbed. The only practical way to avoid this condition and to insure a fairly dry subgrade for a reasonable depth is to place a line of tile several feet deep in the berms under each edge of the road and fill the trench over the tile with gravel, stone or other porous material; or con- struct a waterproof berm and place the tile at edge of berm. The tile would intercept any water falling on the berms or.which might penetrate the roadbed by water standing or flowing in the ditches, or which might rise from underground sourés, and would maintqain a reasonable dry * subgrade, 67 Permeability . Permeability is that property of soils which permits water to flow through the pores or interstices due to gravity without rupture or dis- placement of the particles thereof. Sand and some soils readily permit water to flow through them while other soils such as hard pan, shale, some clays, etc., almost completely resist the flow of water through them. Permeable soils readily become saturated and require quick and efficient drainage. Stability Stability is that property of soils which resists fluidity or being dis- placed. A ball clay is very stable. Soils can be made more stable by thorough drainage. Adding sand to clay or clay to sand makes the resulting mixture more stable. Sand Sand is composed of small granular particles of some form of mineral or stone which occur in nature and all of which will pass a screen 14 inch mesh. The particles are usually very hard and durable but possess no coherence between the various grains, and are therefore very unstable unless properly confined or contain a suitable percentage of clay or other binder. Sandy soils are easily drained and when con- tained or protected make an excellent subgrade for any type of pave- ment. Clay Clay consists of very finely divided particles resulting from the complete disintegration of rocks or minerals. On account of its fine texture it is very retentive of moisture and becomes plastic and unstable when saturated with water. Clay containing a considerable percentage of coarse and fine gravel is more stable, more easily drained and has less capillarity. Clay is difficult to drain and the system of drainage should be designed so as to prevent water from penetrating the roadbed and subgrade and not at- tempt to depend on draining the water from the subgrade. A tough stiff clay will resist the action of traffic better than a short, crumbly or loamy clay. Clay when thoroughly dried out by the sun and atmosphere should retain considerable moisture in the form of “water of combination”. A plastic or “ball clay” is best for road binding pur- poses; it will not slake, and being slow to absorb water, will retain its form and position for a considerable time when immersed jn water, yet retain considerable moisture when dried out. Plastic clays are more difficult to mix with other materials, but produce the best results. They mix more readily after a long rain or continuous sprinkling. Improper or insufficient mixing will likely produce pitting and rutting of the surface, 68 Slacking clays absorb water rapidly and readily becomes suspended in water, forming mud. They are easily mixed with other materials but usually possess inferior binding properties. Clays which shrink on drying out and expand on becoming saturated are not very satisfactory as road binders or for a road foundation. When dry they cause ‘cracking and breaking up of the surface, and when saturated they readily sep- erate or expand. They are apt to produce a dusty surface in dry weather and a muddy surface/in wet weather. 3 Gravel Gravel consists of angular or rounded particles of stone or mineral which occur in nature and which are of sufficient size to be retained on a screen of 1% inch mesh. Gravel composed of a calcarious nature or which contains sufficient clay or other bonding material to bind the par- ticles together, forms a very satisfactory material for a roadbed. It is easily drained and very stable when compacted. Loam Loam is a mixture of clay or sand or both and decayed vegetable matter. Usually loams are easily drained, especially when they contain -a considerable percentage of sand. Loam for road building purposes depends upon the relative quantity of sand and clay contained. Gumbo Gumbo consists principally of clay or silt and a high percentage of decayed vegetable matter. It readily absorbs and retains water, is diffi- cult to drain and when moist has a very low bearing value. It is usually a poor material for a subgrade. Marl Clay containing a large percentage of calcium carbonate is called marl. It has about the same characteristics as clay. Curves Curves in alignment produce a tendency for the water to cut the embankment away on the outside of the curve. Care should be taken in designing ditches where there is a reduction in the grade to avoid deposits and filling up of the ditch due to decreasing the velocity of the water. Drainage on Grades Essential More careful and thorough drainage on our roadbeds is absolutely necessary. Almost without exception, pavements. on clay soils with grades as high as 6, 8 and 10% were damaged where there were no tile underdrains provided. The higher percent grades seemed to augment rather than decrease the damage. This was especially noticeable in "69 cuts. Water flowing in the side ditches on grades readily enters the roadbed at an angle with the ditches by capillarity and gravity. The roadbed became saturated from water due to the snow melting slowly, seepage from adjacent embankments, seepage from different startifications under the roadbed and wet weather springs. Farm Crossings Many roads are seriously damaged by farmers filling up ditches or using too small a tile under the driveways to their residences and fields or in front of their residences. No tile should be permitted to be used for such purposes under 15 inches in diameter. In several instances farmers have sloped their yards to the edge of the road metal instead of to the edge of the berms. The slope of the berms should be main- tained throughout the entire length of the road so as to secure good and quick drainage. Where farmers desire to place tile. in front of their premises or slope the ground to the edge of the road metal they should be required to pave the berms at those places. Otherwise in retentative soils the road surface in front of their premises will likely be ruined. Drainage is accomplished in three ways, viz: Surface drainage, sub- surface drainage, or a combination of surface and sub-surface drainage. Surface Drainage Surface drainage should provide for a speedy removal of all water which falls on the surface of the road and the interception of all water from adjacent land which might otherwise flow on or across the surface of the roadbed. The surface water should always have an opportunity to drain from the roadway as quickly as possible before it has time to collect on or penetrate deeply into the surface, This can be accomplished by giving the road a crown or slope from the center to the sides and keeping the surface firm, hard and smooth. The crown or slope must be maintained, otherwise pools of water will stand on the surface of the roadway, which will soften the surface, subgrade and roadbed. Ditches Ditches should be provided at the sides of the roadway so as to take care of the surface water draining from the roadway and to intercept any water which might have a tendency to flow on the road surface from adjacent lands. They should have a slope of at least 6 inches to 100 feet. With a less fall if there be snow in the winter, the flow of the water will be retarded and may cause trouble. The ditches should be not less than 30 inches below the bottom of the road metal. They should be wide rather than deep. Deep ditches beside the road are dangerous to traffic and are usually unnecessary. A deep narrow ditch is expensive to construct and maintain and is easily obstructed by caving banks, weeds and floating debris. Broad shallow 70 . ; ze ditches are better than deep ones as they will not form gullies at the side of the road so quickly and they retard the flow of water on steep grades. V-shaped ditches have several desirable characteristics. They are not so dangerous, can be cleaned with a grader or smoothed with a drag, keep greatest velocity of current away from the berm, thereby reducing the tendency to wash or undermine the berm, and are easier maintained. To prevent washing on steep grades, the water should be carried under the surface at frequent intervals from the upper to the lower side, and from the lower side away from the road. The water must be disposed of before it. gains force or headway or accumulates in large quanties or has time to damage the road. In deep cuts and on hillsides it is often advisable to dig a bank or storm water ditch above the road on the shoulder of the slope in order to intercept surface water from the hillside and this water discharged into outlets entirely away from the road. In cuts where the grade is in excess of 3 per cent, or where the soil is loose or sandy, it is some- times necessary to pave the gutters with cobblestones, bricks or con- crete, to prevent the formation of gullies in the ditches; shoulders and in the macadam. Usually a guetter 3 feet in width laid on the same, or a little greater slope than the macadam, is sufficient. Such a gutter may replace the shoulder, but it should not be constructed until after the road is substantially completed. Water should never be carried in the gutters or side ditches any farther than necessary. Steep grades require the greatest number of outlets in a given distance. In adjusting the size of the ditches one important consideration should always be borne in mind, and that is, that the velocity of the water should not be so great as to wear away the sides and bottom of the drain, yet of ample capacity to take care of the water at all times. The side ditches should have slopes of one and one-half to one, or two to one, to eliminate as far as possible the danger of washing and undermining of the berme bank, which may cause the filling up of the ditch and be the means of destroying the drainage arrangement. The more gradual the slope the less danger of vehicles overturning at the edge of the ditch. When the road soil is clay or silt, the side ditches should be deep- ened andthe traveled roadway somewhat raised to increase the drainage and protect it against water. Outlets for ditches should be provided at every low point, and should be large enough to carry off the worst flood water quickly. To do this, outlets should be built with a large factor of safety. Crown On many country roads the drainage of the surface soon becomes poor on account of the crown not being maintained. This may be due 71 to a gradual lowering of the wheel tracks on the center of the traveled way, or because of the development of continuous obstruction on the shoulder of the roadway. The shoulders should be kept sufficiently low so that the road surface will drain at all places. They should have a slope of one and one-half inches per foot. The growth of sod or weeds on the shoulders and in the ditches frequently obstructs the proper drainage of the road surface and the speedy removal of water. The growth of sod and weeds on, the shoulders has a tendency to raise the elevation of the shoulders and collect the dust and other refuse which would otherwise find its way to the ditches and be carried away; also collects and retains water in pools along the berms. The surface of the road should be kept clear from leaves, sod or rubbish of any kind. It is essential that both the paved and unpaved sections of the high- way be kept to the designed cross section, to prevent the cutting of ruts, which will hold the water. Clay, when free from water, is stable and some clays offer considerable resistance to the disintegrating power of water ; ‘but when clays are saturated, they become a fluid and are dan- gerous to traffic. 72 SUB-SURFACE DRAINAGE Sub-surface drainage should provide for the speedy collection and removal of the underground water found or which might otherwise find its way in the roadbed from underground sources, or from the surface. or sides of the road. Sub-surface drainage is used where we find ab- sorbant, yielding, retentative soils, springs, ground water or where the road has a steep, longitudinal gradient or where the water must flow with considerable force. Sub-surface drains should intercept and carry away the sub-surface water before it can penetrate the roadway. The level of the water in the drains should be kept well below the material forming the sub-grade and roadbed. Tile Drains Tile serves to lower the water and to dry the roadbed quickly after a freeze, and to remove or intercept the underflow. It is manifest that in some places drains would not be required on both sides of the road. The tile should be placed on the side of the road from which the seepage comes. The tile should be not less than 5 inches in size. If smaller tile is used, good drainage cannot be assured owing to the tendency of the tile to become somewhat displaced and to the liability of the smaller sized tile to become filled and obstructed. Sewer pipe will give better service than farm drain tile. They should be placed not less than three and one-half feet deep below the surface of the road and always below the frost line. It is often advantageous to fill in around the pipe and for several inches above it with crushed stone or gravel, as this increases the capacity of the drain and prevents the earth from getting into the joints. Tile placed in a herring-bone manner and the drains filled with porous material prevents water from flowing under the surface or through the subgrade or grade. Trench drains are not always a suc- cess. Tile assists in maintaining uniform saturation and consequently uniform expansion and contraction. : Sometimes, if the grade is raised, in wet places the trouble will be lessened particularly if porous materials are used. Drainage should become better as time passes as the water forms pores which facilitates the flow. Side drains may consist of narrow trenches filled with broken stone or gravel, or a pipe five or six inches in diameter may be used in the place of the stone, or a pipe may be laid in the bottom of the ditch and covered with the stone. This treatment is particularly applicable to roads built on a side hill on clay subsoil, where the seepage from the 73 side hill would otherwise soften the road foundation and thereby cause failure. The pipe should be laid with open joints true to grade and carried to a proper outlet. It is frequently necessary to construct culverts or lay pipes under the road to convey the water from the upper to the lower side and connect the pipes or culverts with suitable outlets. It may be necessary to construct catch basins provided there are no suitable inlets. Pipe Culverts By increasing the fall, we increase the capacity of the pipe, decrease the size of the pipe necessary, and therefore decrease the cost of the culverts. Furthemore, culverts laid flat will soon fill up, but given a good fall, they will keep themselves clear. If much fall is obtained in cuverts pipe,.the spillway should be paved. Earth should be tamped under and around the pipe in layers, and should be of sufficient depth to prevent the pipe from being broken by traffic; but under no cir- cumstances should a ridge over the culvert be allowed, for it not only endangers the life of the culvert, but is a menace to traffic. Culverts Culverts should be built at low points where outlets are available and existing streams should always be utilized for outlets. All culverts should be covered with a cushion of earth or other material to prevent traffic from coming directly on them. In case of stone or concrete culverts, eight inches of covering will be sufficient. With pipe culverts there should be not less than eighteeen inches of covering; two feet of covering. will be more satisfactory. When culverts of any kind cross the roadway, they must be kept in repair, particularly at the ends and there must be no doubt about their being clear. All culverts and bridges should be planned and con- structed in the most substantial and permanent manner and be of ample dimensions so as to take care of the maximum amount of rainfall. A ditch should never be carried over a culvert but should discharge into the culvert. In designing a culvert the local conditions, area to be drained, maximum rainfall and fall should govern the dimensions. The maxi- mum rate of rainfall is usually figured on the basis of one inch per hour. The area to be drained and the fall can be arrived at in many instances from the government contour maps, which are easily acces- sible. Frozen Culverts Many roads were damaged by culverts freezing up and stopping drainage after a thaw. Culverts should be larger and given more fall than ordinary so as to hasten the drainage and avoid freezing up. 74 Shoulders In clay, loamy or similar soils trenches should be cut through the shoulders making outlets into the side ditches for water that may collect in the metal and on the roadbed during construction and later before the surface becomes hard and waterproof. Such trenches should be eight or more inches in width and slightly deeper than the metal bed. . They should be placed at all low points in the grade and not farther than fifty feet apart in retentive soils, and must be filled with gravel or other ~ porous material before the first layer of metal is applied. 75 PAVEMENTS Width of Pavements ~ The width of many trucks over all is'about 7%4 feet and the width _ from out to out of wheels 7 feet. For two trucks of 7% foot width to pass with safety at a moderate speed requires a pavement 18 feet wide. This gives a clearance between the trucks of two feet and a margin of one foot from wheel to outer edge of pavement. A 16 foot pavement re- quires reduced speed to pass with safety. Where the pavements are too narrow the shoulders receive con- siderable of the traffic and are therefore expensive to maintain. Often the cost of the excessive maintenance would pay for a little additional width. It is not economy to build pavements in excess of 18 feet in width, except on a few roads leading out of some of our largest cities. All highways should be designed to permit additional widening. Width of Pavements on Curves The width of the pavement should be increased on all curves of to degrees and over. The increased width should be on the inside of curve and begin ahead of the point of curvature and extend beyond the point of tangency. Ditches The practice of designing and constructing practically all ditches of uniform depth and width regardless of the drainage and soil conditions is absolutely wrong. The nature of the soil and topography determines ‘to a large extent the depth and width of the ditches. The bottom of the ditches should not be less than 30 inches below the bottom of the road metal. The ditches should be located as far from the roadbed as condi- tions will permit. The outside slope of the ditches in cuts should be not more than 114 feet horizontal to 1 foot vertical and in some soils should be still less. ; Subgrade As increasing the thickness of the foundation does not furnish addi- tional strength in proportion to the additional thickness, and reinforcing a concrete foundation to withstand heavy traffic would cost according ‘to present prices from $1.00 to about $2.50 or more per square yard for the reinforcing, it is obvious that the most economical design will provide for several feet of well drained subgrade at all times and places. This will require a careful study of soil and drainage structures, so as to obtain the desired effect under existing circumstances and conditions. Do not rely on any unusual qualities of the soil but always provide ample drainage, 76 BERMS Slope The slope of the berms when made of earth should have a slope of at least 114 inches to the foot in order to provide rapid and efficient drainage of the berms and road surface. Unless the berms are con-. structed with a fair slope they -soon become too high owing to the growth of sod, weeds and the deposit of dust and other debris thereon, causing the berms to hold water and saturate the berms and subgrade. Several failures have occurred on account of berms being too high and not properly maintained. Width Where the berms are too narrow there is not sufficient lateral sup- port given to the roadbed and subgrade. Where the roadbed is moist and the berms narrow, heavy traffic shoves out the berms causing a settle- ment of the pavement in many places. It has been particularly notice- able that where the berms were 6 feet wide and had a slope of 1% inches to the foot the pavements were usually in better condition. It costs considerable more to maintain a narrow berm. Berms should be built to stand a proportion of the traffic. Porous Berms Berms made of porous stone and thinner at the edges assist in drainage after a thaw. The thawing begins at the surface and the thinner edges thaw out first giving an opportunity for the water that may have collected in the center of the road and on the subgrade to flow to the side ditches. Thickness of Surface or Foundation In order to intelligently design the thickness of a foundation or road surface, it is necessary to know the bearing value of the subgrade, which frequently consists of a variety of soils possessing different character- istics, the bearing and shearing value of the road surfaces, the loads and the manner of their distribution and application, none of which has been definitely determined. Until there is a definite limit arbitrarily fixed for the speed, wheel loads, wheel spacings, minimum thickness, width and resiliency of tires and unsprung weight of trucks no economical design can be made for any type of pavement. The traffic loadings and regulations govern the nature and thickness of the surface, foundation and subgrade. Any attempt to formulate a design under present condi- tions would be an assumption and even if based on past experience might be out of date by the time it was completed. The financial resources of the State will not permit engineers to continue designing and rearranging 77 the design of our highway designs to meet the whims and requirements of the designers of trucks. The practice of locating the line and grade of a highway and then arbitrarily adopting a slab thickness for the entire length of the road without reference to the soil or drainage conditions is neither economical nor logical. Some roads are designed too heavy, others too thin con- sidering the traffic and soil conditions.. Highway engineers should en- deavor to inspect the right of way of all roads proposed for improve- ment, during the winter thaws and when the frost leaves the ground, and make notes of the soil conditions and probable drainage required. Also make survey of local materials that might be used in the. con- struction of the foundation. The surface of the foundation should be uniform and smooth. Inequalities in the foundation should not be taken care of by increasing the thickness of the surface as such inequalities are usually reflected in the finished surface. Where soil and drainage conditions are bad a thin layer of fine stone or gravel placed on the subgrade and a layer of coarse stone or gravel placed thereon will be found advantageous in many cases. A knowledge of weather conditions throughout the year is essential. Bridges Bridges should not be less than 20 feet in width to allow trucks to pass conveniently and with safety and to provide for increased traffic in the future. At the end of all bridges, culverts etc., provision should be made to prevent the subgrade from settling and imparing the surface and inconveniencing travel. Bridges are rigid and there is considerable impact when a moving load leaves the bridge surface and strikes the more or less resilient road surface. The earth back of the walls or abutments should be thoroughly compacted to about three feet below the top of the subgrade forming a triangle and the space filled with stone and thoroughly compacted. Having a considerable depth of stone next to the bridge would take care of the sudden impact and gradually reduce it to normal conditions when the load reached the unsupported road surface. Bridges should be desigried:. Of sufficient strength to carry all loads; Of sufficient capacity to carry all water; Of sufficient width to carry all traffic: Of durable material ; Of neat appearance, 78 CONSTRUCTION Earth Roads | There is an urgent need of the adoption of a system in the location, improvement and maintenance of earth roads, bridges and other drainage structures thereon, in order to avoid unnecessary waste of time and money. Numerous instances have been noted where grading has been done, bridges, culverts, etc., built, farm improvements made, which either had to be abandoned or an exorbitant expenditure made to conform to existing conditions. Before any grading of. any consequence is done or any bridges or other improvements of a permanent nature are made, a survey should be made with a view of determining the best location of the road for future needs and service and all grading, dragging or other improvements should be made in conformity with the established line and grade. : Earth roads will, for many years to come, comprise the largest portion of our road mileage and the adoption of a system of construction and maintenance is almost imperative. Proper drainage, ditches, grading, etc. should be provided and a maintenance system in the form of a patrol adopted, There are a number of earth roads that are being properly dragged but as a rule the work is not done properly or at the right time, there seems to be a general lack of information as to the benefits, purpose and correct manner of dragging. A number of pamphlets have been published and distributed by the State and the Ohio Good Roads Federation, but local communities are continually changing their officials which requires continued instruction on the part of the state to obtain proper main- tenance of earth roads. 79 DRAGGING Purpose The principal purposes of dragging are: To maintain the surfaces of roads constructed of materials which when wet readily become rutted by traffic and which on drying out become more or less firm and hard; to produce a smooth and uniform surface of fills, subgrades and roads, constructed of earth, clay, gravel or materials of similar nature. To facilitate drainage by producing and preserving a proper crown, by smoothing out the irregularities in the road surface; by spreading out the puddles of water and exposing a larger surface to evaporation; by sealing the pores; by keeping the sides of the roadway clean and free from weeds, sod, etc., and by obtaining a more compact and permanent surface thus reducing the formation of dust and mud and the absorp- tion and retention of water and to facilitate traffic and render road surfaces passable which might otherwise be impassable at certain seasons. To distribute the travel by preventing the formation of ruts which the traffic is apt to follow. Very rocky or sandy road surfaces are more likely to be damaged than improved by dragging. It may require considerable time and system- atic dragging before the real benefits are apparent. When to Drag The surface material assumes different properties as it changes from a very wet to a very dry condition. Immediately after a rain the surface is very wet and soft but not very sticky. When in this condition dragging will bail the water out of the depressions, drain much of the standing water off the surface spread out the puddles of water and prevent to some extent the softening of the surface and consequent rutting by traffic, but great care must be exercised to avoid producing a wavy and uneven surface. Dragging when the surface is saturated to a considerable depth has a tendency to destroy the crown and to increase rather than reduce the irregularities. Then for a period the material becomes thicker and more sticky and will adhere to and accumulate in front of the drag and be deposited in piles or rows, leaving a wavy and irregular surface. Following the above condition the surface material will settle and develop sort of a set, yet contain sufficient moisture to be plastic but not enough to adhere much to the drag. This is the best time to drag a road surface; it will slide freely along the face of the drag and can be easily deposited where required; it will compact readily but will not produce mud; it will smear over partially sealing the pores, making the surface less absorbent; it will sort of bake on drying out, forming a 80 rather hard and crisp surface that is not readily transformed into dust or mud. Clay and water when puddled into a mixture becomes somewhat tough and if compacted in this condition becomes very hard and more or less impervious to water. Dragging when the surface is dry is usually a detriment ; it loosens the surface and breaks the seal, making the surface more absorbent, thereby increasing the amount of dust or mud. A heavy drag may be used to smooth a dry surface which has become very rough from neglect or other causes. Drag as often as holes and ruts appear in , the surface. Drag at the proper time after every prolonged rain at all seasons of the year. Drag at the proper time after the frost leaves the ground in the spring. Drag the most traveled roads first. Drag the dryest sections of the road first. Drag just before a freeze and a smooth surface ewill result. Drag when the surface is soft enough to cut easily and in condition to puddle. It is best to work the surface too wet than too dry. Drag when the material ‘will crumble easily if the surface is full of deep holes and ruts. How to Drag The results obtained depend upon the condition of the surface at the time of dragging and-the skill of the operator in manipulating the drag. Pick out and remove all large stones from the surface before dragging. The berms of gravel and macadam roads should be dragged outward so that the earth will not be deposited upon the gravel or ma- cadam surface. Begin at the outer edges first, gradually working toward the center of the roadway. Manipulate the drag so as to deposit the material where required to obtdin a smooth and uniform surface and to secure or main- tain a proper crown. Do not drag much loose material toward the center of the roadway at any one time; just sufficient to compact readily, fill the holes, ruts and depressions and to maintain the crown or raise it a few inches where required. Where the crown is low it should be raised a few inches at a time by several draggings, rather than all at one time. It will compact better, producing a dense baked surface all the way up. Loose earth acts like a sponge and is easily converted into dust or mud and diverts the traffic to the side of the road. Sometimes it will be advisable to use a smoothing drag or clod masher where the soil is very sticky or breaks up into lumps. Should the crown become too high, drag a portion from the center to the sides. The depth of cutting can be varied by shortening or lengthening the hitch, by weighting the drag, by the driver shifting his weight backward or forward or from one oe to the other, and by changing iis amount of skew. SI Where deep ruts or depressions occur in the surface they should be filled by operating the drag with little or no skew. To discharge rapidly, shift the weight to the discharge end. To discharge slowly shift the weight back and toward cutting end. To cut deep, shift weight for- ward and toward cutting end, or lengthen the hitch and increase the amount of skew, or both. The drag should have a steel cutting edge. Always drag the sides of the road so as to keep the weeds pared. Ride the drag where necessary. Drive the team in a walk. If the drag clogs, shift the weight to the extreme rear end of drag. Do not drag sod, weeds or other debris onto the road surface. 82 GRADING Drainage ce Thorough drainage and preparation of a road bed is absolutely essential with any class of material. Neglect of proper drainage means failure and high cost of construction and maintenance. During construction the side ditches should be kept open and at least 12 inches lower than the surface of the existing grade, at all times, in - order to dispose of the water quickly, facilitate construction and produce good results. Drains should always be constructed through the shoulders to the side ditches, at intervals of 50 feet, and filled with coarse stone or gravel to assist in keeping the subgrade dry and to act as permanent drains for the road bed. This will save much time and expense during construction. Cuts In plowing and excavating the cuts, the plows and scrapers do not penetrate to a uniform depth relative to the finished surface of the sub- grade, therefore the material should be removed to such a depth that. the remaining material when-scarified to a depth of at least four inches and harrowed, shaped and rolled, will conform to the surface of the proposed subgrade. This is essential in order to secure uniform density of the material forming the subgrade. Slopes The slopes of the fills and cuts and crown during construction should — conform at all times to the crown and slopes of the finished cross- section. All side slopes should be furrowed horizontally so as to form benches about one foot apart in the original slope before any material is placed thereon in order to hold it in place, prevent slides and to form a union between the old and new material. Fills The fills and subgrade should invariably be compacted by harrowing or dragging and rolling and brought to a true, firm surface without ruts or depressions and with perfect crown. The use of a drag or harrow levels off the high places, helps fill the depressions, prevents bridging by the roller, keeps the grade in a smooth condition for draining and hauling, and is an advantage to a contractor. Uneven distribution and compression of the material forming the fills and subgrade is responsible for much damage to roads and pavements, especially those of the more rigid types. The fills should be formed in layers not to exceed g inches in thick- ness and each layer thoroughly harrowed or dragged and rolled so as to 83 secure a uniform density and compaction of the material forming the embankment. The practice of filling the center first and dumping over the sides to get the requisite width should not be permitted. Alt fills should be sarted the full width at the bottom and carried up with proper grade, crown and slope as required for the finished cross section; this is necessary to obtain good drainage and to secure a firm and compact fill of uniform density. Places inaccessible by the roller should be compacted by tamping. Frozen material should not be placed in a fill as it shrinks and con- tracts under its own weight, which will cause the surface to settle un- evenly. A common fault is over-compression at the center as it is easiest to operate a roller at these points. Where over-compression takes place the earth will expand, and where there is insufficient compression, shrinkage will occur, and in either case the earth will in time restore itself to its original density and volume and cause displacement of the surfacing material. This may require from one to three years or more but it will finally revert to its natural condition. Subgrade The more care and preparation the subgrade receives the better it will serve its purpose and the less it will cost to construct, maintain and repair. The subgrade should be examined carefully for all deficiencies in material, drainage and construction. A properly prepared fill and subgrade is one of the most important problems of construction and one which is too often neglected. More failures have been due to defective subgrade than to any other source. “An expenditure of a few cents per square yard in excess of the usual practice, applied to harrowing, dragging and rolling the subgrade would be money well expended. This will increase the supporting power of the subgrade and consequently the stability of the surfacting material. Should the subgrade become spongy the material should be removed and filled with stone or other suitable material. If it has become saturated with water, plowing and harrowing will assist in drying it. In deep, fine sand and where rolling is impracticable the subgrade should be shaped and straw, hay or fine brush should be laid on the . subgrade, or fine clay may be added and then sprinkled and compacted by harrowing and rolling. This will prevent the first course of stone or gravel from penetrating into a sandy subgrade. The subgrade should contain nothing which is likely to heave, yield or settle and all vegetable matter should be excluded. If the subgrade is not thoroughly compacted the stones composing the surfacing material will be forced into it and wasted. Stability of construction is the prime object to be obtained. 84 If low places are found or depressions develop during construction, the old surface should be loosened so that the new will adhere to the old material; and additional material put on so that the subgrade shall con- form to the proposed grade and cross-section. A road drag can be used to good advantage at the proper time after a rain in shaping and maintaining the subgrade. It will smooth out and accelerate the drying out of the subgrade by spreading out the puddles of water and filling up depressions, thus increasing the surface exposed to evaporation. It also tends to make the surface more impervious to water. Shoulders ; The shoulders should be constructed at the same time the sub- grade is prepared. Many contractors slight the proper formation of the shoulders. Usually only sufficient material is placed to hold the stone temporarily in place. This should not be permitted, as it is very poor construction, spoils the appearance of the road and costs the contractor much more than when made at one time. The shoulders should be constructed at the required slope and maintained so that they will drain readily and should be compacted so that they will absorb as little water as possible. The shoulders should be kept free from weeds. Where the shoulders are constructed of sand, clay should be applied. Where the shoulders are constructed of clay, an application of sand will be beneficial. _ Completing Work The contractor should be required to practically complete the grading, subgrade, ditches and shoulders as he moves along the line of the work. It will cost him less money and is much more satisfactory. It saves much time and expense in moving equipment backward and forward and in plowing or scarifying surfaces that were once loose. 85 GRAVEL CONSTRUCTION Gravel _ Gravel is often used for road building purposes because it is frequently found located convenient to the road and on account of the cheapness of the construction. This results in the use of a great variety of gravel in road construction. Gravel makes an excellent foundation for most types of road surfaces. Most gravel roads have not the wearing qualities of a good crushed stone road, but where good gravel is available in Sufficient quantities it will make a good road for the money invested and easy and economical to maintain. The important qualities which road building gravel should possess are hardness, toughness and cementing or binding power. Of these three qualities, the binding property is due in part to the presence of iron oxide, lime or clay and in part to the angular shape and size of the pebbles com- posing the gravel. Gravel for the wearing surface should not contain pebbles larger — than one inch in diameter. Large pebblessoon cause the surface to ravel and produce a rough surface. A proper mixture of the gravel and binder is of more importance than the kind of gravel used, altho the gravel should be hard enough to resist abrasion. Gravel containing an excess of sand will not bind or form a hard smooth surface and will be expensive to maintain. The pebbles should be angular, for when smooth they are more free to move one upon the other, thus producing less mechanical bond; the irregularities and corners adjust themselves in such a manner as to become wedged or locked. Gravel obtained from streams is usually inferior to pit gravel, as the action of the water has worn the pebbles smooth and round and re- moved practically all the fine binding material. Even if clay or loam is mixed with river or creek gravel, the result is not likely to be as satis- factory as that obtained by the use of pit gravel. However, pit gravel is occasionally found with the same characteristics as gravel found in’ streams. Where such conditions exist about 10% to 20% of fine lime- stone dust should be added. This will overcome any objection due to the lack of fine binding material in the gravel. Clay If there is a large quantity of clay in the gravel it will become dusty in dry weather, leaving the stones loose on the surface, and sticky in wet weather, causing the stone to pull out of the surface of the road on the wheels. Where clay is freely used consolidation may result more quickly, but it is not as satisfactory as if less clay were used with more rolling. Gravel containing a large percentage of clay cannot be rolled 86 successfully while saturated with water as it will pick up and adhere to the roller wheels even tho the surface be flooded. Such gravel should have just sufficient moisture in it to compact it and not adhere to the roller. It may be puddled and compacted by harrowing and dragging and then ‘rolled when the moisture has partially dried out. A gravel road is very difficult to bind successfully by flooding, rolling and grouting without the addition of limestone or other suitable screeninigs. If there is suffi- cient clay present to form a wave of grout in front of the roller it wilf adhere to the wheels, leaving the surface rough and full of depressions. — If there is not sufficinet clay present to produce a wave of grout the flooding will wash it down into the gravel, leaving the surface stone loose and with little or no fine material to bind it. If an excess of clay works to the surface, making its sticky or has a tendency to ball up, there is too much clay. If the surface loosens in dry weather there is not sufficient clay or binder, or it lacks binding qualities. In selecting clay for road purposes select the stickiest clay available. If the clay sticks to the thumb, it is reasonable to suppose that it will stick to the gravel, if it will not stick to the thumb it is safe to assume that it will be a poor binder. . Screenings The object of the screenings is to wedge and hold the gravel in place and prevent internal movement. The screenings should be finely divided and graded so as to fill the interstices between the stone. Limestone or slag screenings are probably the best available. The fine material acts mechanically to keep out the water, thereby keeping the subgrade dry, and to support the fragments and will act chemically to bind the fragments into a more or less solid mass. Construction A gravel road is easy to construct and repair and when properly constructed makes a very satisfactory road surface. The success and subsequent maintenance of a gravel road depends largely upon the manner in which it is constructed and the care it receives during the first year after construction. Long periods of dry, hot or wet weather are detri- mental to gravel roads not protected with a suitable binder. Care should be taken so as to distribute the traffic over the entire surface as much as possible in order to prevent tracking or rutting. Gravel roads should have wide roadbeds and the shoulders should never be less than four feet in width so as to distribute the traffic over the surface. As soon as a layer is in place it should be sprinkled and alter- nately harrowed and rolled so as to consolidate the gravel from the bottom to the surface of the layer. The harrowing prevents the bridging of the gravel at the surface by the drag or roller and causes the gravel to com- 87 pact at the bottom of the layer first. This process continued long enough will produce a dense and compact mass. It is the principle the farmer uses to compact the earth to form a seed bed for grain. If the gravel is well compacted the wear on the road will be greatly reduced. The road should be dragged as often as may be necessary to preserve the crown and maintain the smooth surface. -The amount loose gravel will compress under the roller varies according to the kind and sizes of gravel and methods used in construction. Compacted gravel will occupy from 2/3 to 34 of its volume when loose. The tendency of a newly constructed gravel road is to form wheel and horse tracks due to the concentration of the traffic at these points. They should be kept filled by frequent dragging, this will distribute the traffic, and assist in compacting the entire surface. If the depressions are not kept filled, water will stand in them, weakening the bond, cut the ruts deeper, wash waves in the crown as it flows to the ditches, soften the subgrade and in a short time the traffic will cut through the surfacing material into the subgrade. Before using the drag all large stones which have worked to the surface should be removed. The dragging should be ‘done while the surface is wet. The proper bonding and compacting of the material is the most important part of the construction of the surface of any road. Loam is often used as it is easily applied, but it is more easily affected by the water and frost and when wet may act more as a lubricant than as a binder. A surplus of clay or loam will give a smooth road without much rolling, but such a road is liable to become dusty or muddy according to the conditions of the weather. An excess of binder is often used to reduce the cost of construction by decreasing the amount of work re- quired, but such a practice adds to the cost of maintenance and the road will be less durable. The gravel should be harrowed to assist in compacting, to aid in mixing, to equalize the spreading, to securé an even distribution and uni- form density, to overcome any pockets of either fine or coarse material and to prevent a wavy surface. The gravel should be deposited in layers from 3 to 6 inches thick and compacted from the bottom up. Gravel deposited in too heavy a layer will never become consolidated as it should. A disc harrow is best for mixing clay with sand and gravel» A spring tooth harrow should be used where there are likely to be pockets of fine or coarse material or to loosen the gravel after it has been sacrificed, and should be the only one used in compacting gravel. It takes several weeks for a gravel road to thoroughly compact. During this period careful attention should be given the road surface, and holes, ruts and depressions repaired at once. A spike tooth harrow separates the coarse from the fine, working the fine to the bottom and the coarse stone to the surface. 88 Crown A gravel road is more susceptible to penetration by water than any other type of surfacing material. The surface should be kept smooth and well crowned so as to shed water easily and quickly. The crown should be about 34 inch per foot. The usual curved crown much flattened at the center is not very satisfactory for gravel roads on account of their tendency to flatten out which holds water after a rain and hastens wear at the center. The crown should increase more rapidly from the center to the four foot points than is customary for a macadam roadway. Cross Section The nature of most gravels makes it necessary to drag the road surface at.various intervals in order to preserve the crown and maintain a smooth surface, therefore the feathered edge cross section will be found most satisfactory for gravel roads. The shoulders being covered with gravel will not wash so readily the surface will be more easy to drag and the tendency to carry undesirable material from the dirt shoulders on to the gravel will be obviated. The feather edge is more easily constructed and gives a wider road surface for accommodating passing vehicles. The feather edge should extend td within at least six inches of the outer edge of the berme. This method requires but little more material which will be mostly offset by avoiding the cost of the expensive berm type of construction. The shape of the finished subgrade being a flat crowned surface is easy to construct and affords good drainage at all times during and after construction which is an asset to the contractor and to the road. Voids There should be sufficient screenings to fill the voids and to obtain the maximum cementing effect. If there are voids in the road surface the chance of failure is increased. The voids may be due to lack of fine material, insufficient harrowing, rolling or sprinkling. Lumps of clay will bridge the interstices between the stone even under constant rolling but the bridge will break down eventually either from pressure, moisture or traffic or a combination of these. This will cause the surface to ravel. Freezing Weather No attempt should be made to bind gravel in freezing weather. The moisture in the gravel freezes almost instantly on coming in contact with metal wheels causing the metal to pick up the gravel leaving the sur- face full of holes. The gravel which has adhered to the wheels will make further depressions in the surface, leaving it wavy and irregular. Maintenance All repairing should be done while the road is in a wet or moist con- dition, preferable when the water is still standing in the depressions on 89 the road surfaces, so that workmen can see just where to place the new gravel and about how much is required. Always shovel the gravel into the depressions in order that the proper amount of gravel will be de- ° posited at the right place on the road surface. Patching should never be done when the roadbed is hard and dry, for then the new material will not adhere to the old surface and becomes scattered over the adjoining surface, tending to loosen it, or is soon ground into powder making dust and mud. The old surface should be loosened before placing any new material thereon. Do not make repairs too high as this may produce two depressions where there was but one before. WATERBOUND MACADAM Probably the first theory as to the bond of a stone road was the interlocking -of the pieces of stone, and the compacting of the finer particles into the voids that gave the entire strength; but this is not all, for chemical changes take place in a stone road through the action of water that assists in binding the fragments together. It has been very clearly demonstrated by laboratory work later supported by actual results in the roads, that if particles of stones are rubbed together in the presence of water there is formed from the stone and water a fine paste that has considerable binding power. Water alone when brought into close contact with road stones, screening and dust, as in grounting and rolling, will produce a somewhat stable bond. The formation of this-bond continues as long as there is abrasion on the road and moisture is present. The bond thus increases in quantity and becomes hardened in time, and if present in sufficient quantity is an effective bond, but the formation is usually too slow to prevent ravelling and rutting under action of motor driven vehicles. Water has the effect of leaching out of road materials certain natural binders chemically effecting a union between the particles of stone. A bond is developed by hydrolizing some of the rock components which results in the formation of colloids. Water containing small amounts of - carbonic, humus, or other acids, is capable of slowly decomposing many minerals commonly found in rocks used in road building. Water alone is capable of acting chemically upon many rock constituents causing a breaking down into secondary products of the primary minerals. This is the principle underlying waterbound construction and sets up what is known as the “bond of a road.” The chemical action bonds the road surface by the formation through solution and evaporation of chrystal bodies which upon chrystallization forms a more or less rigid bond. Stone The most important characteristics of road stone are hardness, tough- ness and cementation value. It is important that the stone for surfacing material be of uniform texture and of uniform size otherwise unless the stone is unusually soft, a rough surface will be the result in a compara- tively short time after the road is open to traffic. Where the surfacing material is limestone or slag, the best results are usually obtained for waterbound macadam by using, stone that will pass through at 314” circular opening and be retained on a 2” circular opening. Stone that will pass through a 31%” circular opening and be retained on a 34” circular opening may be used with very satisfactory results for the bottom course, if properly screened and care is used in construction. It is very important where such size stone is used that it be thoroughly harrowed in order to OI bring the coarser particles of stone to the surface and leave the finer particles on the subgrade. Stone from three-quarter inch to one and one- half inch in size should-not be used in road construction except in the ‘bottom of the lower course. It is difficult to key the stone or grout a road properly when small size stone is used or when it is mixed with the larger size stone. A small quantity of 3¢ to 34 inch stone can be used to advantage after the large stone have been keyed but before applying _ the screenings. The application of too much of this size will loosen the larger stone. The stone should be well rolled before applying the screen- ings so as to wedge the smaller stone in place. Soft stone should be of larger size than hard stone, for the soft stone will be materially reduced in size by rolling. Sharp angled, irregular shaped stone key better and produce less voids than round or flat stone. A stone of good binding nature will frequently wear much better than one without, altho it may not be so hard. Unscreened or crusher run stone produces an unsatisfactory road owing to the irregularity of the sizes of the fragments and the variation in the proportions of the several sizes and their unequal distribution in the Petia Ss The larger size stone will withstand more abrasion; it is not so easily displaced or crushed; it will key better, thus producing less voids, and _it is not so liable to produce a wavy road; it is more easily rolled and the voids are more easily filled; it will not pick up so readily when grouting, and it will wear and give better satisfaction than the smaller size of stone. ; Screening Stone The size of the stone is not altogether determined by the size of screens used owing to the fact that the speed, length and inclination of the screen, nature of the stone, opening of the crusher, amount of stone delivered to the screen, the cleanliness of the stone with reference to clay and soil, the kind of screen, whether shaker or revolving, and the perforations, whether square or round, and the fabric of the screen, whether wire mesh or perforated boiler plate, all determine the size of the stone going through the screen. If a circular screen is revolved rapidly the stone will not be as well screened. There will be more of the finer stone carried over with the ‘larger stone. The same situation is obtained by giving the screen a greater inclination or by overloading it. This is also true of a shaker screen, but not to so great an extent. The opening of the crusher should be set somewhat larger than the maximum size of stone required so as to produce about fifteen per cent tailings. If the crusher is set according to the maximum size specified an excess of the smaller size of stone will result, which in road construc- tion is very undesirable, especially for the upper course. A soft stone 92 will produce more screenings and a larger opening of the crusher is re- quired. Dirty stone will not screen as well as clean stone, therefore larger screens and larger openings of the screens are necessary to pro- duce the size stone required. A square mesh screen will permit of larger stone passing through it than a round, perforated plate, and will screen the stone a little better Screenings It is the finer particles of dust that form the cementation or binding properties of the stone and which are most readily acted upon by various agencies, producing chemical reactions that increase the natural binding properties of the stone. Screenings should be sufficiently fine to be easily worked and flushed into the voids or crevices between the larger particles. Unless the voids are thoroughly filled the pavement will act as a drain; the water will percolate through the surface and the subgrade and bermes will become saturated with water, and a slow but constant sinking of the stone into the subsoil and a gradual rising of the soil into the stone takes place. The cohesion of the surfacing stone is destroyed and the stone will finally become a mass of holes, ruts and stone, and the pavement will not pre- serve the natural soil from contact with water, thus destroying one of the important objects of a surfacing material. The fine dust and screenings assist in wedging the larger particles in place, thus adding stability to the road surface. A waterbound macadam road is subjected to the action due to traffic and to some extent that of the elements. The chemical decomposition of stone is so small that it has not much affect on the road. The binding of the coarse aggregate is due chiefly to the filtering through and cement- ing of the very fine particles. Spreading Great care should be exercised in dumping and spreading the stone so that the coarse and fine fragments will not become separated thus producing a layer of unequal density and an irregular surface, which will not wear evenly. Unless every detail is carefully watched there is — certain to be a lack of uniformity in thickness and texture. ‘If care is not taken there will be a collection of the finer stone where it is dumped with the result that the voids in these finer stone will not become filled. The road will not wear well at these points and in a short time holes and ruts will develop. The stone should be uniformly distributed over the road, both as to size and thickness. When stone is dumped in piles the smaller fragments consolidate to a greater or less extent to the center of the heap. When the pile is levelled the coarse stone are usually raked to the sides leaving the center almost intact and a wavy road results. It is of the utmost importance 93 that there be uniformity as to thickness, evenness and homogeniety. No irregular depths of stone, no irregular thickness of courses, and no pockets of fine or coarse material, no variation in sizes, etc. The stone should not be spread too far in advance, the rolling screen- ing and watering should be completed as soon as possible after the stone is spread. It requires much longer time for the subgrade to dry out sufficiently to roll the stone when a course of stone is placed on it. The stone becomes damp and it is more difficult to fill the voids and will require more sprinkling. There should be no disturbance of the road surface during construction and while the courses are in an uncompleted condition; horses’ hoofs and wheels of vehicles are detrimental to the work; but when the macadam is completed and dried out the sooner it is used the better. Harrowing Stone The stone should be harrowed before rolling so as to shake the various size pieces of stone into place and allow the smaller pieces to take their position at the bottom of the layer and the larger near the top; to assist in securing an even distribution of the fine and coarse particles of stone; and to produce'a more uniform and even surface. The stone will not creep as readily in front of the roller when harrowed and will key better. A spring tooth harrow should be used where there are likely to be pockets of fine or coarse material or to bring the coarse stone to the surface after it has been scarified. A spike tooth harrow is best for shaking the stone into place or for leveling the surface. Spreading Screenings The screenings should be scattered thin with a swinging motion of the shovel. They should be spread lengthwise of the road so as to avoid separating the coarser from the fine. If scattered crosswise the fine dust will be deposited on the near side and the coarser screenings on the far side of the road surface. At all times the surface of the stone should be visible and be in contact with the roller. If the screenings are scattered too thick or in shovelfuls, they will bridge and will not go down in and fill the voids of the under stone. This will result in raveling and a hole in the road at Such points by the action of the travel, as the screenings will be jarred down leaving the upper stone loose and unbound. It will also take more time and water to finish a road properly where an excess of screenings is applied. If spread thin the voids will be more easily filled, the stone will key better, a more even surface will result and the stone will not be so easily picked up by traffic. An excess of screenings produces a suction by the roller when grouting, which will pick up the stone leaving holes in the road to be filled with screenings, which soon develop into holes under the action of the traffic. The screenings should not be dumped upon the surface of the stone, nor scattered from wagons but should be deposited in piles at the roadside. 94 The wheels and horses’s hoofs produce depressions in the stone which become filled with screenings which will not wear well, and holes or ruts soon develop in the surface at these points. The screenings will become bridged where they are dropped on the stone, and the voids will. not be thoroughly filled, nor the stone properly keyed, and in a short time the surface of the road will become loose and disintegrate. More rolling and water will be required to finish a road in this manner. No more screenings should be used than is necessary to fill the voids and leave a very thin covering over the larger stones. Depressions in the upper course should not be filled with screenings, but with stone of the size used in that course. Rolling and Grouting The object of rolling is to compact the stone, keep the surface even, - assist in filling the voids and to bind the road.. The wear on a road is greatly reduced by a smooth surface. The ability of a roller operator is an important factor in macadam road construction. The finished appearance of the road surface depends to a great extent on the skill used in operating the roller. Stone fragments are most readily fixed in position when exposed to moderate pressure in the beginning. The macadam should not be rolled when the subgrade is soft or yielding, or when the rolling causes a wave-like motion in the macadam or sub- grade. Continuous rolling under these conditions will force the clay or subsoil up through the stone to the surface and the shearing and bearing value of the road surface and the binding action of the dust will be lost and the stone will sink into the subgrade and in a short time the road surface will be destroyed. If the road shows a wavy motion after the roller passes over it a few times, it may indicate too much moisture, in the subgrade.. If such is the case the rolling should cease for a few days allowing sufficient time for the subgrade to dry out, when the rolling may again be con- tinued. With some stone a “crawling motion” may be induced when the rolling is continued. This may result from an excessively hard stone, the sharp corners becoming rounded, and if continued long enough the stone will become like marbles. A slight sprinkling of stone screenings will prevent this action. Before spreading Screenings all humps in the stone should be levelled and depressions filled with additional stone of the same size as the rest of the course, all wheel tracks smoothed out, and the roller run over such places so that the surface of the stone is hard and smooth and of even cross section and longitudinal slope. The rolling should continue while the screenings are being spread so that the rolling will assist in settling the screenings to the bottom and fill all voids and to keep the roller in contact with the surface of the stone, thus producing and preserving an even wearing surface. If an 95 excess of screenings be used more rolling and water will be required and poor results will be obtained. The most important thing to obtain is, the proper compaction or interlocking and grouting of the broken stone. Almost always the rolling of the different courses is less than it should be for the best results, and the deficiencies in rolling are attempted to be made up for by using the Screenings too soon and too profusely. Roads that have been consolidated by traffic are largely held to- gether by mud and in time may become fairly smooth and hard in dry weather, but become soft and muddy in wet weather. By using a large quantity of screenings mixed with the stone, the amount of rolling is lessened but at the expense of durability. If there is an excess of screenings between the stones the rain will wash it out leaving the sur- face loose and unbound. The best road is made with the least amount of screenings consistent with cohesion, providing the metal surface of the road is properly formed and of sufficient strength. A smooth even wearing surface economical to maintain will this be obtained. The number of superficial yards rolled per day will vary according to the different conditions, the class of material, the amount of screenings and water used, the gradient, the capacity of the roller, and the amount of rolling considered necessary. A steam roller will not compact more than from 50 to 75 cubic yards of stone in a day of ten hours and will not do that well unless plenty of water is used. From 4 to 5 cubic feet of water to a cubic yard of stone is required to water bind a macadam road. This quantity of water may be increased somewhat in extremely dry weather and may be lessened in wet weather. The quantity of water will vary according to the methods and machinery used. No matter how well the road has been graded nor how well the stone has been applied the surface will not be durable unless it is thor- oughly watered, rolled and grouted, so as to make the surface water- tight. The road should be flooded so that the water will flush the fine material into the voids and a wave of grout will move before the roller and the rolling and grouting continued until a solid surface is formed. The roadway should be rolled and watered until it “puddles” on the sur- face thus showing that the voids are thoroughly filled. The roller should follow immediately after the sprinkling cart or wagon. Care must be taken to keep the tires of the sprinkler clean as they will pick up the dust and stone causing bare streaks and holes on the surface. Flushing may cause the dust to settle so that the bare places show again. Cover these with more screenings and sprinkle and roll until the whole surface is thoroughly puddled and grouted and uniformly covered with a thin coat of grout. A frequent mistake is made in applying too much dust. Just enough to cover the stone at all stages of the finishing should be used, and no more, Too much dust forms ruts, travel becomes con- 96 centrated in these ruts and water standing in them will soften the stone ~ and cause the ultimate destruction of the road surface. Special attention should be given to consolidating the berms, as there is a tendency for the roller to push the stone sidewise, and if there is nothing to resist this action the stones become open in the center and the stone will not key together ; these openings become filled with screen- ings which are easily displaced by the elements. and traffic; it will re- quire more screenings and water to finish a road with insufficient berms. — It is impossible to bind a road properly where the shoulders spread apart or where there is a soft or yielding subgrade. The berms should be so Shaped that the water will drain off while binding the road so as to avoid softening of the berms and subgrade. The object of the berms is to prevent the spreading of the stone and provide a uniform slope for the wheels when turning off and on the road metal. Thickness If stone is put on a road in layers less than 4” in thickness it will be very difficult to key and bind the stone properly, it will require more dust because the voids cannot be reduced to a minimum. A. layer of loose stone more than 6” cannot be compacted with a roller easily. The voids aggregate between 40% and 50% of the volume of the layer when the stone is spread loosely on the roadway. The roller will consolidate the material and will reduce the percentage of the voids from 30% to 40%. Itis not altogether the amount of metal that makes a good road but the manner in which it is put on. It will require about 1.33 cu. yd. loose stone and 0.30 cu. yds. loosé screenings to make 1 cu. yd. stone when rolled, compacted and water- bound. These quantities may vary slightly from the above figures. A soft stone will crush and leave a smaller percentage of voids when rolled than a hard stone, hence a slightly greater depth of stone will be re- quired, but the additional stone will be offset by decreasing the amount of screening needed about the same proportion. The quantities will vary slightly according to the methods of screening and spreading the stone and manner of constructing the roadbed and road surface. Voids The practice of constructing a macadam road without thoroughly filling the voids with some material of a strong binding nature, should not be permitted. If the voids in the lower course are not thoroughly filled, the action of the rain and traffic will carry the finer particles of dust through the upper course to the lower course causing the stone in the upper course to become loose and to ravel, forming holes and ruts. Furthermore, the traffic will force the clay up through the stone which will act like a lubricant between the various particles of stone and de- stroy the shearing and bearing value of the road surface. If the voids a7 in the upper course are not thoroughly filled and bound with a proper binding material, the surface will soon ravel forming holes and ruts and the wearing value of the road will be greatly impaired. All ashes, litter or other material should be removed from the road surface before rolling as it bridges and prevents the filling of the inter- stices with binding material and the proper keying and bonding of the stone. The stone are easily displaced and holes and ruts quickly develop at these points. Voids may be caused by insufficient fine material, har- rowing, rolling or sprinkling, to chunks of clay or other material in the screenings or to improper spreading of the stone or Screenings. Crown The object of crowning a road is to provide drainage and enable the surface to shed water. The road should be sufficiently crowned so that the water falling upon it will run quickly to the gutters. The shoulders should have a slope of 114 inches per foot. A low crown tends to distribute the traffic over the surface. A heavy crown cauSes the traffic to concentrate in the center of the road where there is an even footing, but ruts soon develop due to the concentration of the traffic and the additional abrasion and shear produced by the higher crown. A crown about 14” to 34” per foot is required for waterbound ma- cadam. A greater crown is required on grades, on account of the water having a tendency to follow the wheel tracks along the road. Freezing Weather No attempt should be made to bind the macadam in freezing weather. The moisture in the material freezes almost instantly on coming in con- tact with the metal wheels, causing them to pick up the stone and Screen- ings, leaving the surface full of holes. The material which has adhered to the wheels will make further depressions in the surface, leaving it wavy and irregular, — BRICK PAVEMENTS Brick Pavements A brick pavement properly designed and constructed with a good quality of brick of correct shape makes a very desirable pavement for most purposes. Some brick pavements have given remarkable service for years while others have given but little wear and poor results. Brick manufacturers and engineers have both been at fault. We have con- tended for a number of years that lugs on brick, over sized brick, round corners, and cement grout filler, were a serious detriment in the con- struction of a durable Pavement. Recent investigation confirms above statement. Frequently the quality of the brick has been condemned when o8 the fault was in the design and method of construction. The crushing strength of good brick is several times that produced by any load likely to be carried by our pavements. Brick should not be burned too soft or too hard and should be well annealed and reset burned so as to wear evenly and not be shattered. The brick manufacturer in order to reduce the number of brick, quantity of material and freight per square yard of pavement, to reduce the percent, of loss in the rattler test, and in handling, and to produce a_ smoother and better looking brick, placed lugs on the brick, rounded the corners, repressed and made them larger. Many engineers and brick interests have been advocating the design of rigid types of pavements. This has been a serious error and has re- sulted in the loss of many thousand dollars to the state and counties. Brick pavements fail largely through poor drainage, expansion, contrac- tion, vibration or fatigue, frost and settling of sub-grade. We believe a bituminous filler and a bituminous cushion would give much better re- sults. Standard Size Brick The manufacturers and engineers should adopt a standard uniform size of brick, wire cut, square edges, without lugs and not over 3 inches thick. Suggest 3” x 4” x 81%4” as a convenient and economical size. Advantages derived are: Better and more thorough vitrification. More uniformity of vitrification. Less laminations. Interchangeability of brick of different manufacturers. Convenient in making repairs. 3 Reduced weight per square yard of 25% when laid flat. Reduced initial cost of brick per square yd. 33 1/3% when laid flat. Economical to manufacturer. Brick adapted for use in buildings. Ready sale of cull brick. Requires less filler. Makes a better pavement. Makes a smoother pavement. Filler It has been a universal practice to fill the joints in brick pavements with sand, cement, cement grout or bituminous filler. A cement, cement grout or bituminous filler properly constructed forms practically a water- proof surface. A cement or cement grout filler has not as a rule given satisfactory results or country highways, and the use thereof should be eliminated, except on monolithic or semi monolithic construction. 2, Cement filler crushes brick where no expansion joints are provided. Brick is injured by expansion more than wear. Cement joints partially filled cause the brick to spall off. Where sand cushion is used a mastic filler should always be used. Sand is a poor,conductor of heat, hence the surface of a pavement with said cushion becomes hotter than a monolithic pavement and more ex- pansion occurs. In monolithic pavements the expansion is not quite so much aS more of thé heat is absorbed by the subsoil. Rich cement grout causes the brick to be crushed even where pro- vision is made for expansion. Poor quality of grout crushes before the brick are damaged but does not protect the edges of the brick so well. Rich cement grout filler produces most too rigid pavement where long distances are paved at one time. Cement grout filler gives fairly good results in cities where the drain- age is good and quick and the pavement is constructed in short sections or blocks which allows for some expansion to take place before adjacent sections are paved. Square vs. Rounded Corners Square corners on brick produce less hammer and vibration by traffic consequently cause less damage to the brick than rounded corners. Square corners do not spall any quicker than round corners when grouted with cement or mastic filler. Square corners require more care in handling. The corners are not more likely to spall than the thin filament of grout produced by rounding the corners of the brick. Lugs on Brick Lugs on brick are not only unnecessary but a decided detriment to to brick pavements. They produce a rougher pavement and increase the wear on the corners of the brick at the joints. Brick are usually of bet- ter material than the filler so why not have as much brick and as little of filler as possible? The joints can be filled with fine sand, cement grout, using fine sand, neat cement, mastic filler, asphalt or tar. The Smaller joint requires very little if any more cement if neat cement grout is used. Curbs . Curbs placed along brick roads on country highways usually fail to perform the purpose for which they were intended and are often a serious detriment to the surface and foundation. They are frequently raised or displaced by frost which leaves the subgrade without any lateral sup- port, prevents the water from flowing rapidly from off the surface and forms pockets that hold water, which readily saturate the subgrade and road bed. Curbs are therefore a needless expense and it. would be 100 economy in most instances to supplant the curb with a gravel, stone, slag, or preferably a bituminous berm. A bituminous berm allows for ad- justment, gives additional width to the road, prevents the growth of sod or weeds, affords better drainage and is easy and economical to main- tain. Cushion : Bituminous Cushion A bituminous cushion makes a firm waterproof, resilient mass which is not displaced by water or traffic. The cushion should be composed of sand and 7 to 10% of asphalt or tar and have about the consistency of sheet asphalt. | Sand Cushion Sand is a poor conductor of heat hence the surface of a pavement with a sand suchion becomes hotter than the surface of a monolithic pavement and consequently more expansion occurs. Sand partially fills the joints of the brick and is easily displaced by water. It frequently becomes saturated and where it is of unequal thickness or density as is usually the case there is unequal expansion by frost which results in the cracking of a rigid surface. Granulated Slag Granulated slag makes a much better cushion than sand as it sets up somewhat in time. It is not waterproof nor has it the resiliency of a bituminous cushion. Foundation Practically all of our old brick pavements have been built with flexible base and filler. Altho traffic conditions have changed materially the same principle is still applicable. Railroads have in several instances used concrete foundations under their tracks in wet and springy places, but they always place several inches of ballast between the ties and con- crete base. It would not be economy to build a concrete slab sufficiently thick to withstand the action of frost without cracking. It would be economy and produce better results to expend more money on drainage, in securing a dry subgrade and less money on expensive foundations. Some brick pavements on broken stone or gravel foundations have given years of service and withstood heavy traffic. There has been too much emphasis and reliance placed on laboratory tests and not sufficient con- sideration given to service tests. Engineers should bear in mind that brick pavements on country highways are often subject to a number of conditions not usually found in city pavements, namely, good and rapid- drainage, better distribution of traffic, arch action between curbs, raised curbs give better support, subgrade contained by curbs, more lateral sup- port due to higher park strips and curbs, paved in short sections, etc. IOI BITUMINOUS MACADAM Road Binders A binder for a macadam road should be a cementing material that will hold the aggregate firmly in place, that will render the material prac- tically waterproof, that will form a stable surface and yet not destroy the elasticity and resilience of the mass. A binder that will protect the surface from the disrupting strains to which the road is likely to be subjected and at the same time be reasonably low in first cost and economical to maintain. The durability of the road surface depends upon the power of the materials of which it is composed, to resist those natural and artificial forces which tend to destroy it. The life and stability of a macadam road surface, to resist the action of traffic depends largely on the interlocking of the pieces of stone and the retention of the fine particles of dust and screenings which serve to bind together and hold in place the coarser particles of stone constituting the road surface. The keying and inter- locking of the stone and the binding of the dust and screenings, must be accomplished by either chemical or mechanical means, or both. Many so-called road binders are essentially lubricants and when put on a road surface in any considerable amount will penetrate into the road lubricating the aggregate and disintegrating the road surface instead of binding it. Great care should be exercised in selecting materials for dust layers and road binders. Some binders produce a rigid bond, others a more or less resilient bond. The latter are preferable for country high- ways. BITUMINOUS MATERIALS Properties A bituminous material should set up or harden soon after application so as to produce a mechanical bond of considerable stability. The setting up of a bituminous material depends upon a volatile solvent which will evaporate rapidly after it is applied to the road. The bitumen should consist of a soft basic material of good adhesive consistency. No bitumin- ous materials possessing sufficient body to bind a mineral aggregate of stone chips will penetrate to any extent farther than the voids in the surface will permit. A good bituminous binder should have a heavy body when set up and maximum cementitious and adhesive qualities. It should remain plastic at low temperature so that it will not crack or chip off; and be sufficiently solid that it will not bleed under summer temperature nor be picked up by passing vehicles. ; I02 Bituminous materials which have not the property of setting after being applied do not possess sufficient body to bind a mineral aggregate of stone chips, and they absorb dust and dirt readily, forming mud to be washed away in wet weather. No permanently fluid product is satis- factory for a carpet medium. The majority of residual petroleums are chemically stable and contain but a small per cent of volatile distillates, hence are not suitable for carpet mediums. Asphalt oil should contain a high percentage of good asphaltic base, ° otherwise the material near the surface will become loose owing to the lubricating qualities of the oil. Free Carbon The less free carbon (finely divided carbon or soot in suspension) , a road tar contains, the better its binding qualities. Tars produced at high temperatures usually contain large amounts of free carbon, while those produced at low temperatures contain the least free carbon (soot) and are the best for road purposes. Free carbon has no binding prop- erties. It acts as a filler, giving the tar a false consistency, reduces the adhesive action of the tar, preventing to some extent itS penetration into and absorption by the road stone. Tars used for road purposes should not contain more than 15% of free carbon. Fixed Carbon Fixed carbon is formed by ignition and should not be confused with free carbon. Fixed carbon is indicative of stability of the material and does not injure its binding qualities. High Free Carbon Tars Tars produced by the destructive distillation of coal at high tempera- tures usually contain 20% or more free carbon. They are not satisfactory as road binders. Low free carbon tars are produced by the destructive distillation of coal at low temperatures or by cracking oil vapors during the manufacture of carburated water gas. They usually contain less than 10% of free carbon and are more suitable for road purposes. Tars con- tain more than 15% of free carbon weather rapidly. 103 BITUMINOUS CONSTRUCTION . Chips | Chips are applied to prevent the binder from adhering to the wheels and to give stability to the bituminous material. If applied in excess the carpet will become saturated with them, resulting in the disintegration of the surface and the formation of dust. Gravel produces a wavy carpet owing to its tendency to roll and pick out under traffic. Sand will not produce a tough mastic with bituminous materials; it has a tendency to make them short; it is too fine to produce sufficient mechanical stability in a carpet thicker than % of an inch. . Chips which are hard and thoroughly screened so as to pass a % inch screen and be retained on a % inch screen will give the best results for uSe in a carpet medium. They should be applied lightly and evenly over the surface; about 3g of an inch will usually be sufficient. Do not apply large chips on a bituminous surface as they will either crush under the roller, forming dust, or project through the surface, or will break the set or bond of the larger stone. The dust will prevent the proper adhesion and penetration of the seal coat. If the stone projects through it will be more easily displaced by traffic and it will injure auto tires. Large chips prevent the proper bearing of the roller on the surface and even compression of the stone chips and the proper filling and sealing of the surface voids. Stone Stone for bituminous surface macadam should be hard so as to produce as little dust as possible during construction and under traffic and should be clean and free from dust or fine material so that the bituminous material will readily penetrate and adhere to it. Fine aggre- gate or stone from an old road which have become rounded should not be used as they will not key properly and move freely upon one another. The stone should be evenly distributed over the surface about 3%4 inches deep, loose measurement. This will produce a surface about 214 inches thick after rolling and compacting, Surface Treatment The object of a surface treatment is to prevent the formation of dust, the loss of the fine particles and the displacement of the coarse aggregate and to bind the aggregate together. It is not the purpose of.a surface treatment to lay any quantity of dust which may be present on a road, but to prevent the formation of dust, therefore a clean, practically dustless surface is the first prerequisite of any form of surface treatment. On roads where the ‘products of wear and dust formation are reduced to a minimum the road may become dusty from outside sources’as no road surface will remain dustless for any considerable length of time, 104 Dust Layers Many bituminous dust layers are lubricants and possess little or no adhesive or cementing properties and will not rapidly develop them. “If applied in excess they either lubricate the aggregate, destroying the natural bond of the road, or remain on the surface to be transformed into an oily emulsion by the action of the rain and traffic. A few dust layers form a mat or carpet coat on the road surface which does not adhere to the road metal. This mat soon breaks and peels off and instead of protecting the road surface isa serious detriment or damage to it, aS the traffic produces a hammering effect upon the road metal where the mat has been displaced, causing deep holes and ruts. There is no mechanical bond in a surface application and the results depend entirely upon the adhesive and cementing properties of the bi- tuminous material used. Unless there is adhesion between the carpet and the surface of the road, it will pick up the wheels wherever any bleed- and the surface of the road, it will be picked up by the wheels wherever any bleeding occurs. | Materials which are inherently oily and lack the property of develop- ing cementitiousness are of doubtful value for road purposes. They tend to destroy plant life and mar the appearance of the fences and other works of beauty and art along the roadway; and readily soil vehicles, wearing apparel, household furnishing, etc. If used at all they should be applied uniformly and lightly; about one-twelfth to one-eighth of a gallon per square yard will usually be ample, just sufficient to moisten the dust particles so that they will not be lifted by the wind or traffic. Do not apply a bituminous dust layer to a new waterbound macadam or gravel road until it has been thoroughly compacted and seasoned. Carpet Coat 2 All holes, ruts and depressions in the surface should be repaired con- siderably in advance of applying the carpet, so as to become firmly com- pacted or bonded. Repairs will not likely compact after the carpet coat is applied, nor will bituminous material form a good bond with loose material. Deep holes and ruts repaired by filling with broken stone and applying cold oil or tar will not hold or bond. Do not sweep a road surface when wet, as the brooms will paste a coat of mud over the surface of the stone. Sweep the surface when dry and util it is clean and voids about 1%4 inch deep are formed in the surface. This will give the binder a chance to adhere to the stone and will, to some extent, prevent the carpet from shoving and forming waves and depressions. Do not elimiate surface irregularities by the applications of extra quantities of stone chips and bituminous material, as the increased thick- ness will produce an unstable surface. Much of the success of a carpet coat depends upon the uniform and even distribution of the bituminous materials. A uniformly applied carpet should adhere and conform to 105 the original surface after application. If applied too hot it may collect in puddles or run off the road surface leaving an uneven distribution of the ~ material. Do not apply a bituminous carpet on a wet, dirty or dusty road surface. No bituminous materials suitable for a carpet coat will adhere to wet, dirty or dusty surfaces. The carpet will adhere to the wheels of passing vehicles, leaving portion of the surface bare, which soon develop into holes and ruts. Do not apply a carpet medium to a newly constructed waterbound macadam or gravel road until it has been well compacted -by traffic; it will not adhere well and will soon disintegrate. Do not construct a bituminous carpet thicker than %4 inch, and even then it will have a tendency to push into bumps and waves by traffic. This tendency can be lessened somewhat by applying it in two course and filling each course with hard, clean stone chips. Do not use fine sand or dust, as it makes the surface too plastic and unstable. Do not construct at one application a thick carpet coat with bitumin- ous material sufficiently fluid at ordinary temperature to apply cold, or with a bituminious material though sticky and sufficiently viscous to require hot application yet will not harden to semi-solid consistency after application. The surface will become slippery and pick up, soiling clothing, household furniture, vehicles, etc. If more screenings are added, it will shove under traffic and waves and bumps will develop which con- tinue to increase until they become one or more inches thick, while in other places depressions form with little or no carpet covering. It is almost impossible to repair a surface so formed without removing the entire carpet. Do not apply an oil product on an old tar surface. The fresh oil residue softens the old tar, forming a non-adhesive mixture which will not harden and which disintegrates rapidly, Do not expect a bituminous carpet to give good service if left covered with sand, dust or mud. They are readily ground into the carpet by the traffic, causing it to become short and to disintegrate radily. It is very desirable and important that the carpet medium penetrate the surface of the road to some extent. A priming coat of light bitumin- ous binder is essential as it will penetrate the surface more readily. The heavier binder will adhere better to the aggregate and spread more evenly where a priming coat is used. A soft asphaltic cement which contains a volatile flux or a very viscous refined tar are best suited for carpet mediums, as they harden rapidly upon exposure. A bituminous carpet will give good service on roads subjected to a combination of automobile and light auto truck or horse drawn traffic. They are not very satisfactory for roads or’ streets where there is an excess of horse drawn vehicles. Automobile traffic is 106 necessary to iron out and amalgamate the cuts and abraisions of the horses’ hoofs and steel tires. Bituminous Penetration The foundation course should be thoroughly filled with screenings and dust, rolled and puddled until it is firm and hard, so as to prevent wasting and excessive or uneven penetration of the bituminous material.. Unless the foundation course is well bonded and constructed, the bitumin- ous materials, which are more or less plastic especially in warm weather, will not have sufficient strength to hold the surface stone in place. Do not spread a layer of surface stone and attempt to fill the voids in the lower portion thereof with screenings before applying the bituminous binder. The voids cannot be filled properly with either screenings or bituminous material in this manner. The voids will become filled with water, disintegrating the binder. When the water freezes it will break the bond of the binder, producing an unstable surface. The screenings cannot be applied evenly nor the voids be filled equally and the dust becomes scattered over the surface stone, interfering with the adhesion of the bituminous binder. The best results will-be obtained by thoroughly sweeping, cleaning and blowing the dust off of the foundation course until the larger frag- ments are visible and voids begin to appear in the surface, and then applying a priming coat of-a very adhesive bituminous material suitable for a carpet medium applied cold before placing the surface stone thereon. Do not cover this application with stone chips or other material. The surface stone should be placed directly on it and rolled before it sets up. This method will seal the foundation stone and bed and bind the bottom of the surface stone. A serious objection to most binders for penetration construction 1s that in warm weather they bleed and the road loses much of its stability due to the plastic condition of the bitumen and to the fact that he voids are mostly filled with bitumen possessing but little inherent strength, in- stead of screenings and fine graduated material. Where the traffic is heavy and concentrated there is a marked tendency for roads of the penetration type to squeeze out, forming broad depressions, holes or ruts, owing to the bitumen possessing insufficient strength to resist the shear and com- pression. These depressions may eventually become deep enough to collect debris and hold water, which will hasten the deterioration of the road. On city and village streets, this tendency is not so great, as the traffic is usually distributed over the surface and often in a diagonal direction because of the constant passing of the various vehicles. Rolling It is important that the stone be rolled until thoroughly compacted and keyed, but not enough to materially crush the stone into small frag- 107 ments or to close up the surface so as to prevent the bituminous material from penetrating the surface readily before the application of the bi- tuminous material. A proper bedding, consolidation and binding of the stone cannot be obtained by rolling after applying the bituminous material. The cooling of the bituminous materials produces a false set in the stone where they are not compacted and which cannot be overcome by any amount of rolling. If the bond between the stone is broken it will not readily seal or amalgamate. Continuous rolling under these conditions tends to cause the stone to slide about rather than key together. Do not roll the first application of chips too much, it reduces them to dust. Kentucky Rock Asphalt This type of pavement is now giving good service. It is essential that the rock asphalt be of uniform quality, contain the proper amount of asphaltic content, and be put down in a proper manner. 108 CONCRETE CONSTRUCTION There are so many factors which enter into or affect concrete con- struction that it is difficult to obtain a uniform product or accurate placement thereof. There is a tendency to design more closely than the results of construction would warrant. The fundamentals of concrete - are simple yet in practice they are almost universally violated. Points to be observed are: Clean sand, aggregate, water, reinforcing and forms. ‘Good quality of cement, sand, aggregate and reinforcing. Sand and aggregate properly graded. Correct proportions of cement, sand, aggregate and water. Proper mixing, placing and curing. ; Construct substantial forms so as to maintain all lines true to design and in such a manner that the forms can be easily removed without injury to the concrete. For fine work paint forms with paraffin oil, so as to prevent injury to concrete and forms. Economic Proportions Concretes having the same aggregates, cement, mixing, placing, curing and age and same relative proportions of water and.cement have approximately the same strength regardless of the amount of cement used so long as there is sufficient cement to coat the surfaces of all the particles of sand and aggregate. ; Concrete should fill two requirements. 1st. It must be of sufficient strength to meet the conditions of the design for which it is to be used. 2nd. It must be sufficiently plastic or mobile to place properly and economically. To maintain the same mobility with concrete consisting of different aggregates, requires a variation in the amount of water according to the surface area of the aggregate used. To obtain concretes of equal strength and mobility requires a variation of both the amount of water and cement according to the surface area of the aggregate. The surface area of the aggregates, ratio of cement to water and aggregates for different degrees of strength and mobility should be carefully determined by laboratory tests so as to form a basis for eco- nomic design. Tables of the foregoing relations between the various aggregates and cement proposed to be used should be made and the concrete proportioned accordingly. Concrete of a definite quality should be specified. Under this condition if a contractor uses a wet mixture to secure mobility and reduce labor of placing, he must use more cement and vice versa. 109 Cracks in Concrete Pavements Cracks are produced by materials in the fills or subgrade having different densities, absorbent, retentive, expansive, fluid and stabilizing properties, changes in temperature and moisture, friction on subgrade, improper or insufficient drainage, and arched subgrade. Usually the ground under the edges of the slab absorb the most mc ‘sture and drys out the quickest, thus producing a bridging of the slab, and tensile stresses in the bottom of the slab when expansion occurs. On drying out a cantilever effect is produced resulting in tensile stress in the surface of the slab near the center thereof. Frequently the berms spread leaving the edges of the slab with very little support. Materials pos- sessing different densities, absorbent, etc., properties produce unequal expansion and settling of the subgrade. To provide sufficient reinforcing and slab thickness to overcome aforesaid condition would be too expensive for most highways. It is evident that most of the Steel should be placed across the pavement. About 80% of the steel should be placed transversely across the pave- ment. Wire mesh affords the best bond for the amount of steel used. The amount of reinforcing is based largely upon the individual opinions of the engineer. It is common practice to use from 25 to 40 pounds of steel per 100 square feet for a 16 foot roadway. Where construction joints occur a slab of concrete two feet wide should be placed under the joint so as to maintain the surface of the pavement at the joints at the same level. Reinforcing Good concrete will withstand compressive stresses but not tensile stresses to any great extent. The object of reinforcing is to take care of the tensile stresses produced in concrete by loads, impact, changes in temperature, changes in the moisture content of the concrete or subgrade, friction on subgrade, settling of subgrade, shear, to hold the concrete in place where cracks develop, and to lessen the fatigue caused by inter- mittent tensile stresses, and to prevent and reduce the number and size of cracks, thereby saving in maintenance costs. Do not expect reinforcing to take the place of poor materials, poor workmanship, poor design or a lean mix. See that the reinforcing is properly spaced and placed and held in place by wire or other suitable material. The effective results of rein- forcing depends upon proper placement of the steel and the quality of the concrete obtained. Avoid the use of dirty, rusty, greasy, painted or galvanized reinforc- ing, as an effective bond can not be made between concrete and steel in such condition. A good way to clean reinforcing steel is to drag it in loose sand, dry earth or road dust and then wash with a hose. Storage of Cement Cement stored for a longer. period than 30 days should be pro-- tected from moisture in any form. Cement exposed to moisture or free circulation of air will take up moisture resulting in a loss of strength and slower setting properties. Cement properly stored retains its strength indefinitely. Construct air tight and water proof warehouse. Make floor air tight and moisture proof. Elevate floor at least 12 inches above the’ ground. Locate warehouse above flood water. Seal doors and windows. Make floor double with tar paper between. Stack cement against the walls. Stack bags alternately lengthwise and crosswise. Cover cement with tarpaulins, burlap, hay, straw, or other suitable dry material. . Inspect warehouse from time to time to see that the cement has not sprung the floor or walls. Do not disturb the cement unnecessarily as it exposes the cement to the air. Curing Concrete This feature of concrete construction seems to be the one’ most fre- quently neglected. The concrete should be protected from the sun, frost, wind or a free circulation of air for about to days, otherwise the exposed surface will not harden properly. Sand, clay, sawdust, straw or canvas affords a good protection if kept damp at all times. Placing Concrete in Cold Weather Heat water used in mixing. Thaw frozen sand or aggregate before using. Mixed concrete should have a temperature of at least 70 degrees. Place concrete in forms immediately to avoid loss of heat. Protect concrete from loss of heat immediately after placing. Heat reinforcing, metal forms, etc., by steam jets or hot water before placing concrete. Protect concrete with hay, straw, canvas, burlap, sawdust, sheathing, housing in the work, stoves, firepots, steam, etc., for at least six days. Do not remove forms until after testing the concrete to see that it is sufficiently set up. This is best accomplished by removing a small portion of the form and pouring hot water on the exposed concrete. If the concrete is frozen hot water will soften it. Do not depend upon chemicals to lower the freezing point or to protect the concrete but provide ample heat and protection in the form of covering, housing etc. MAINTENANCE AND REPAIR Records of Costs, Repairs, Etc. There is very little reliable data available relative to the cost, repair, _ maintenance and failures of our highways. No one is directly responsible or specially charged with the duty of keeping a record of costs and sys- tematic notes of the conditions affecting failures, methods and materials employed in making repairs and results obtained and apparently no one has assumed the responsibility. Engineers have been free to discuss and describe new designs or methods of construction but have almost entirely neglected to study, compare and record the conditions pertaining to and causing road failures and in so doing have overlooked one of the most important features con- nected with highway construction and maintenance. The art of making economic and scientific road repairs requires a high degree of skill, orig- inality and much resourcefulness on the part of the engineer. The knowl- -edge and skill must largely be derived from practice and a comparison of notes of others as but little information of value can be obtained from text books. Repairs are usually the result of failures and every failure has a cause. In making repairs an excellent opportunity is afforded to study, analyze, compare and record the conditions precedent and under- lying the cause of failures and to supply reliable data upon which to base our future calculations and which forms the basis of our service records. In fact a study of service records is of far more importance than ‘a study of design for the design is directly or indirectly dependent upon the service obtained and must necessarily be modified from time to time to correct or avoid defects in design or use which made the repairs necessary. There are several factors that should be given special consideration in making repairs. (1) A study of the conditions existing prior to the failure. (2) A study of the conditions at the time of the failure. (3) A careful analysis of the conditions that contribute indirectly to the failure. (4)