Page:Highway Needs of the National Defense.pdf/127

Rh application of the same or even lesser loads. Some of the road effects of vehicular load are cumulative.

Applied loads may cause slight movements of the stone particles composing a so-called nonrigid road surface. If, by reason of the manner of load application, these movements tend to occur in the same directions under successive load applications, the condition of the road surface may rapidly deteriorate. In this manner corrugations are formed in gravel road surfaces.

Photo by Ansgar Johnson 92989—49——-9