290 



EXPERIMENT STATION EECOED. 



Relation of road maintenance to traffic, W. D. Sohiee (EngHn. Rec, 10 

 {191 Jt), No. 22, pp. 582-584). — Studies of traffic and repair on Massachusetts 

 highways with reference to the Influence of volume, weight of units, relative 

 number of rubber and steel tired vehicles, and cost of maintenance are re- 

 ported. 



The largest cost of upkeep on macadam roads in Massachusetts is said to be 

 due to heavy automobile travel and heavy hauling on narrow tires. Traffic 

 values of gravel and water-bound macadam roads are given in the following 

 table : 



Traffic values of gravel and water-'boimd macadam roads. 



Notes on the selection of pavements for heavy-traffic roads, H. G. Shirley 

 {Engin. and Contract., Jt2 (1914), No. 2Jf, pp. 531, 538). — An outline of the fac- 

 tors involved in the selection of i)avements for use on country roads subjected 

 to heavy traffic, including excessive loads hauled by tractors, is given. 



It is stated that before selecting the type of pavement to be used a more or 

 less accurate census of the different kinds of traffic should be taken and an 

 estimate made as to the possible increase or decrease of the different kinds.* 

 The following criterion for the selection of the type of pavement is suggested: 

 " Where the annual cost of maintenance of a less durable type of road sur- 

 facing vv'ill exceed the annual cost of maintenance of a more durable type of 

 surfacing, plus 4 per cent on the excess cost of the more durable type over the 

 less durable type, the more durable type should be used, and vice versa." 



State management of public roads, its development and trend, J. E. Penny- 

 backer (U. S. Dept. Agr. Yearhook 1914, pp. 211-226, pis. 2, figs. 3).— In this 

 article, dealing mainly with economic phases of the subject, it is stated, with 

 reference to the progress of state road management, that forty-two States have 

 thus far established highway departments for educational or administrative 

 work, and of these thirty have made actual appropriations in aid of road con- 

 struction or maintenance. " In all, $208,000,000 had been appropriated from 

 state funds between 1891 and January 1, 1915, for construction, maintenance, 

 administration, and educational road work, and a total of about 31,000 miles 

 of improved roads is the evidence to show that this expenditure was not in 



