Abstract: In a running test, vehicle wheels are mounted on rollers. Each roller receives torque corresponding to the running resistance, which is a value corresponding to the running resistance applied to the vehicle on actual ground. The actual friction coefficient between the wheels and the rollers is calculated. The running resistance is corrected such that the actual friction coefficient becomes equal to the friction coefficient on actual ground that is calculated based on the slip ratio of the wheels with respect to the rollers. This approximates the running resistance applied to the vehicle by the rollers to the running resistance applied to the vehicle on actual ground as the torque is applied to the rollers in correspondence with the corrected running resistance. This prevents the drive force produced by the vehicle in the running test from becoming different than the drive force that is produced when running on actual ground.

Abstract: In a running test, wheels 2 of a vehicle 1 are mounted on rollers 3. Each roller 3 receives torque corresponding to the running resistance N, which is a value corresponding to the running resistance applied to the vehicle 1 on the actual ground. Further, in the test, the actual friction coefficient ?ch between the wheels 2 and the rollers 3 is calculated. The running resistance N is then corrected in such a manner that the actual friction coefficient ?ch becomes equal to the friction coefficient ?j on the actual ground that is calculated based on the slip ratio of the wheels 2 with respect to the rollers 3. This approximates the running resistance applied to the vehicle 1 by the rollers 3 to the running resistance applied to the vehicle 1 on the actual ground as the torque is applied to the rollers 3 in correspondence with the corrected running resistance N.