SCIENCE IN HIGHWAY CONSTRUCTION 333 



Since the advent of automobiles, particularly those capable of being oper- 

 ated at high speeds, it has become evident that $100 a mile a year is wholly 

 inadequate for the maintenance of macadam roads, even if they be only of the 

 width of the Massachusetts state highways, and that in order to keep such stone 

 roads in perfectly good condition at least $300 a mile a year should be provided. 



Figures in the possession of the Massachusetts Highway Commission show 

 that about 53 per cent, of the destruction of state highways is due to auto- 

 mobiles. In seven counties near London, England, the percentage of increased 

 cost of maintenance, due to automobiles, has been recently reported to be from 

 22 to 77 per cent., and this condition is probably more or less the same through- 

 out England. 



Mr. Compton, county surveyor of West Cornwall, England, reported 

 in 1910 that in 41 counties the cost of maintenance of broken-stone 

 roads had increased in ten years, since the advent of the self-propelled 

 vehicle, forty-one per cent. 



Mr. F. C. Carpenter, county surveyor of the AVest Eiding of York- 

 shire, stated at the First International Eoad Congress at Paris in 1908, 

 that the average cost of maintenance of the roads in his district in 1890 

 was $482 per mile, hut at that time had increased to $798, reaching 

 in some cases as high as $3,900, while in others it was as low as $73. 

 On the average it was $1,120 for urban roads and $584 for rural roads. 

 He attributed the greatly increased cost in later years to the use of the 

 roads by motor vehicles. 



These conditions have been generally recognized elsewhere, both at 

 home and abroad. The Route Rationales in France, reputed to be the 

 finest roads in the world, especially those built of the softer limestones 

 in southern France, have been so destroyed by motors that their main- 

 tenance, at any reasonable cost, as water-bound roads have become 

 almost impossible. 



These facts are sufficient to show the damage that motor vehicles 

 are doing to our roads of the water-bound type, but it must be remem- 

 bered that if the traffic consisting of horse-drawn vehicles had in itself 

 increased to the same extent as the number of motor cars now using our 

 roads, the cost of maintenance would have increased to a large extent. 

 Before 1900 there was no demand for trunk line roads to be used by 

 horse-drawn vehicles in the same way that they are now used by motors. 



The number of self-propelled vehicles is increasing every year. 

 Mr. Maybury, county surveyor of Kent, England, states that the in- 

 crease in England in the year ending December 31, 1910, was no less 

 than 36,935 and that this is more than likely to be maintained. In 

 New York State more than 81,000 were licensed in 1910, in Massa- 

 chusetts over 35,000. In the latter state more than one third of its 

 vehicles are motor driven. On some of the roads near Boston auto- 

 mobiles furnish more than sixty per cent, of the traffic, and, during the 

 summer, ninety per cent, of the vehicles used on the leading state roads 



