Page:Popular Science Monthly Volume 80.djvu/337

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SCIENCE IN HIGHWAY CONSTRUCTION

Since the advent of automobiles, particularly those capable of being operated 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 automobiles. 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 throughout 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 West Riding of Yorkshire, stated at the First International Road 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 maintenance, 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 remembered 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 increase 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 Massachusetts over 35,000. In the latter state more than one third of its vehicles are motor driven. On some of the roads near Boston automobiles 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