"A study was conducted to (a) investigate the effects of soil surface conditions on one-pass drawbar pull capabilities of a wheeled vehicle, (b) relate optimum drawbar pull to soil strength as measured by several instruments, (c) develop tentative equations for predicting optimum tractive coefficient, and (d) determine effects of tire characteristics (tread pattern and deflection) on drawbar pull. One hundred and six drawbar pullslip tests were conducted with a 3/4-ton M37 truck at a gross weight of 7240 lb. One tire size (9.00-16, 8-PR), two tread patterns (smooth and nondirectional military), and two tire deflections (15% and 35%) were tested. Surface conditions varied from dry and firm, to wetted with small amounts of water, to flooded. Asphalt surfaces also were tested" (p. xi).