WARTIME emergency showed the inadequacy of existing off-the-road transport, and hurriedly organized research did not solve any of the basic problems. Postwar research has explained many fundamental ideas, such as that of ground pressure, and has stressed the importance of the concept of two-dimensional soil loading imposed by a vehicle.
The principles of a quantitative relationship between the performance of a track and a wheel were formulated, and the soil properties responsible for vehicle performance have been defined. The effect of grouser action and tire tread was clarified, and new laboratory methods of working by means of scale models were developed.
The limitations of present design trends were examined, and the necessity for new concepts has been emphasized. Only very slow progress toward this goal is anticipated unless active support for the necessary research program is given by interested agencies.