To enhance the precision of a collision test by reducing the deviation of the actual position of collision from the set position by a simple method.

For calculating the mean free running velocity Va1, Va2 for running from respective traction release position F1 and F2, to set collision position R1, R2 while taking deceleration into account, the preliminary running tests for the higher speed vehicle A1 and the lower speed vehicle A2 are performed. Corresponding to the deceleration rate of a set running speed V2 to a second mean free running speed Va2 of the lower speed vehicle A2, the delay time of a lower speed vehicle A2 to arrive at the own set collision position R2 is set ΔT2, and the thinking distance of anticipated free running distance of the lower speed vehicle A2 is L2(Δt2). Corresponding to the deceleration rate of a set running speed V1 to a first mean free running speed Va1 of the higher speed vehicle A1, the delay time of the high speed vehicle A1 to arrive at the own set collision position R1 is set ΔT1, and the virtual thinking distance is L2(Δt1). The difference of thinking distance L2(Δt2) and the virtual thinking distance L2(Δt1)is calculated as correction distance ΔL2, the start point S2 of the lower speed vehicle A2 is shifted by the ΔL2 for the collision test.