Traffic ana' capacity of a given roadway to support a given amount of traffic stands in close relationship with the condition in which it is maintained. This is so well known that, in the leading European countries, excellent systems of road-administration are iu vogue, certain features of which might with much advantage be copied in the United States, where the subject of the proper maintenance of roads rarely receives the attention which its importance demands.
Measured in terins of the life of draught-animals and the wear and tear of vehicles, the advantage of maintaining roadways in the highest condi tion would be evident from economical considerations alone, as the follow ing example, given by Gillinore, will demonstrate: Take the case of a well made broken-stone road clean and dry, and compare it with the same road in a wet and muddy condition. It appears from the formula established by Sir John Macneill that " a stage-wagon weighing r5oo pounds, in order to carry a load of r5oo pounds at the rate of 5 feet per second (3X iniles per hour), will require the constant exertion of a force of 9434 pounds on the dry and clean road; while to move it at the same rate on the same road in a muddy state will require the constant exertion of a force of 119:yi. pounds." Here, therefore, is an increase of about 28 per cent. of force expended, 3.vhich increase is due entirely to the neglect of the condition of the road surface. Taking the case of a road between two cities, ten miles apart, and assuming that a certain amount of freight will have to be conveyed over the road each dav, whether the road be in g-ood or bad condition, it has been established that if the assumed traffic conld be carried without un usual fatigue by the daily service of fifty-four draught-animals when the road is in good condition, clean and dry; when the road is covered with dust the number of animals required to perform the same service will be in creased to sixty-three; and when this dust is converted into mud, the num ber required will be sixty-nine.
From these data it is calculated that the extra cost of conducting- the traffic on the roaci, due to its neglected condition, will amount to five thou sand dollars per year. In this comparison the same road-bed has been under consideration—a good substantial one—in the one case kept clean, and in the other covered with dust or mud. If the comparison be instituted between
a good road and an inferior one, the contrast will be even more instructive. The accompanying tabular statement, based on the experiments of M. Morin, exhibits the actual relation of animal force to traffic on different kinds and conditions of roads. The load and vehicle are assumed to be the same in each case: IT7(1111 respect of the width of roadways there is no fixed rule. This will depend upon the amount and nature of the traffic that the road is calculated to sustain. The narrowest roads are found in mountainous districts, as in Switzerland, the Tyrol, etc. In Germany the width varies from 6o feet (including foot-way) to zo feet, for roads intended for heavy teaming. In Prussia the width varies from 4o feet to 25 feet. In France there are four classes of roads: (t) 66 feet in width, of WhiCh 22 feet in the middle are stoned; (2) 52 feet, of which zo feet are stoned; (3) 33 feet, of which 16 feet are stoned; and (4) 26 feet, of which 16 feet are stoned.
In England the roads are comparatively narrow, the averag,e being about 25 feet. In the United States there is no uniform practice. The rules laid down by Gillmore are followed in a general way in the well populated districts. These are as follows: For the principal thoroughfares prepared for vehicles between cities and larg,,-e towns a width of from 27 to 3o feet will be ample, but this width should be increased within or near the cities to 4o, 5o, or even 6o feet, where the amount of traffic is large and where there is considerable light traffic and pleasure-driving. For cross, branch, and ordinarv town and country roads the width of the stone bedded portion may be reduced to from 16.;'. feet to 17 feet, which will be sufficient for two wag-ons of largest width to pass each other without dan ger of collision. The width of the principal streets of cities is usually greater than that of the roads above described. In this particular certain American cities afford conspicuous examples.
Passing now to another branch of the subject—namely, paved roadways iu towns and cities—a number of diverse systems demands consideration.