METHODS OF MAINTENANCE. BROKEN-STONE ROAD. There are two general methods of maintenance, which may be called (1) continuous maintenance and (2) periodic repairs. By the first system the waste on account of traffic is supplied gradually as it is worn off by adding a patch here and there, and so the full thickness of the road is constantly maintained; while by the second system the road is permitted to wear thin, and then an entirely new surface is added, although this system does not exclude small repairs, but limits them to the timely filling of holes and ruts to check more extensive damage to the road. The system of constant mainte nance is the one generally employed in Europe; while in America periodic repairs seems to be the more common, although both systems have their ardent advocates.
Those favoring continuous maintenance claim (1) that it is the only system that gives a constantly good road, since with periodic repairs the road is seldom good, being bad just after repairs, becoming passable after a time, and then deteriorating until re paired again; and (2) that continuous maintenance is the cheapest in the long run. Those favoring the periodic system of repairs claim (1) that a well built road will wear uniformly until so thin as to need re-surfacing; (2) that the system of continuous mainte nance does not give as good a surface as the other method, since the new material is constantly being added at every point to supply the loss of wear, and this material must be consolidated by the traf fic; and (3) that the system of maintenance by patching is exces sively expensive, requiring a needless amount of material and labor.
There seems to be an irreconcilable conflict between the theories of the two sides; but in practice, under similar conditions, there is not as great a difference as a statement of the theories seems to indicate, the difference in opinion being largely due to a difference in the conditions assumed. In France, where the maintenance of broken-stone roads has been the subject of and careful observation by the officers of the Corps of Roads and Bridges, the system of continuous maintenance is employed on roads of mod erate traffic, i. e., roads 18 to 20 feet wide having a traffic not ex ceeding about 600 tons per day; and the system of periodic repairs is employed upon roads of great traffic, i. e., roads 18 to 20 feet wide having more than 600 tons per day. These limits would doubtless vary with the nature of the road material, the method of construction, the climatic conditions, the character of the traffic, etc. It is claimed that the system of periodic repairs "is growing in favor in France, and in 1893 more than half the stone employed in making repairs was applied under this system. The method is used exclusively in general repairs of the macadamized streets of Paris." *