The objectives of this study were to evaluate the tractive requirements of different configurations of log-hauling trucks and to recommend devices that will improve their tractive ability. Drawbar pull tests were conducted to determine the relative gradeabilities of a tandem drive-axle tractor configured with a pole, triaxle, and quadaxle trailer. The triaxle and quadaxle configurations require, respectively, 19 and 34% increases in tractive ability of they are to have gradeabilities equal to that of the pole-trailer configuration. Central tire inflation (CTI) and automatic slip regulation (ASR) are two promising devices for achieving such improvements.