388 EXPERIMENT STATION" EECORD. 



gressional committee on federal aid in the construction of post roads is given, 

 showing the aggregate costs of average examples of various types of road con- 

 struction in different States, the unit costs for excavation and broken stone, 

 and the average cost for labor and teams. 



Repair and maintenance of hig-hways, L. I. Hf.wes ( U. 8. Dept. Agr., Office 

 Pub. Roads Bui. 48, pp. 11, pis. 3, figs. IS). — This bulletin considers the repair 

 and maintenance of highways as subjects separate from their construction, 

 dealing principally with macadam roads of all liinds, gravel and sand-clay 

 roads, and earth roads. In addition the maintenance and repair of various asso- 

 ciated classes of roads, such as sand-oil, oil-gravel, brick, and concrete roads are 

 briefly considered in connection with the major classes. Considerable data are 

 given on resurfacing and surface treatment of roads, particularly in the region 

 north of the Ohio and east of the Mississippi Rivers, and in some parts of 

 England and France. 



The importance is brought out of an accurate and comprehensive traffic census 

 as a preliminai-y to highway improvement and a guide as to the necessary 

 quality and quantity of material for maintenance purposes, particularly noting 

 the work of the Massachusetts Highway Commission (E. S. R., 28, p. 684). 



It is Btated that the rapidly increasing automobile traffic on highways has of 

 necessity modified the methods of road construction and maintenance. In 

 this connection the action of motor trucks and automobiles upon road surfaces 

 and the reaction of road surfaces upon automobile and motor truck tires are dis- 

 cussed and statistical data given, all of which indicate the destructive action on 

 both road and vehicle. It is concluded that since the use of motor trucks for 

 commercial purposes is rapidly increasing the final estimate of the economic 

 advantage of using automobile trucks must include as a factor the increased 

 cost of construction and maintenance required upon highways. 



Good roads yearbook (Official Oood Roads Yearbook U. S., 1913, pp. VII-\- 

 51,8, figs. 4). — This book contains a large amount of information in regard to 

 the construction, maintenance, and repair of roads and bridges and road admin- 

 istration as practiced in the various States. 



Horse, truck, and tractor, H. N. Casson, R. W. Hutchinson, Jr., and L. W. 

 Ellis (Chicago, 1913, pp. XII+200, p?s. 29). — In this book are given statistical 

 and other data which indicate the rapidly increasing expense of maintaining 

 horse power for use on farms and in city and highway transportation. From 

 comparative data, based on efficiency and economy in actual operation, a prac- 

 tical solution of cheaper power is suggested in the use of motor trucks for city 

 and highway transportation and in the use of tractors for draft and belt work 

 on the farm. It is pointed out, however, that owing to the small size of some 

 jobs of hauling, the cost of mechanical power In these cases is greater than 

 the cost of horse power so that it is necessary to keep accurate account of all 

 operating expenses on all jobs and so to reduce them that the saving effected 

 on large jobs will compensate the losses from the smaller jobs. 



It is also brought out that the use of horse power can not as yet be entirely 

 eliminated on average and small-sized farms owing to the fact that so far no 

 economical and efficient small farm tractor has been put on the market. In 

 this connection the importance is emphasized of making a careful study of local 

 conditions and requirements so that an economical distribution of work may 

 be made between animal and mechanical power. 



The following chapters are included in this work: The Horse-Cost of Living; 

 Motor Trucks — The New Freighters ; What Motorized Highway Commerce 

 Means to the Business World ; Motor Transportation Considered in the Light 

 of Scientific Efficiency; Why the Cause of Civilization Demands a Horseless 

 Age; Motor Transportation Considered as an Aid to Industrial Advance; 



