Problems Of Off-Road Transportation

Off-road transportation or land locomotion mechanics differs from the usual concept of highway engineering in regard to the relationship between a motor vehicle and the environment of its operation. The basic philosophy underlying highway engineering is that of modifying the environment by means of pavement design to fit the needs of a wheeled vehicle. Off-road transportation or locomotion differs in that soil is the medium in which the vehicle moves and there is no opportunity to transform the existing conditions, much the same as an airplane cannot modify the air in which it travels. Off-road vehicle performance is directly related to the shearing strength and deformation characteristics of soil as they affect tractive effort and sinkage. The status of some current (1963) mobility research projects dealing with deformable soils is summarized. The soil value measurement and evaluation programs for off-road transportation purposes should prove to be of interest to the highway engineer in a more comprehensive understanding of subgrade behavior relative to pavement choice and design.