Abstract: A vehicle dynamics model and a cross-wind model were constructed using TruckSim software to
study the stability of a tractor semi-trailer in cross-wind. Digital simulations were carried out at different wind
heading angles, wind speeds and vehicle speeds with step steering input to analyze different vehicle responses
of the roll angle, the yaw rate and the hitch angle and then to obtain the critical vehicle speed and critical wind
speed for the tractor semi-trailer with stability driving. The trailer turns over first when the wind speed is more
than the critical value. The tractor semi-trailer turns to be drifting, rollover and unstable seriously when the
vehicle speed is larger than the critical value. The analyses show that the effect on the tractor semi-trailer with
step steering in a counter direction cross-wind is stronger than those in a positive direction cross-wind. The
results can provide stability analysis references for tractor semi-trailers in cross-wind.

Key words: automotive safety, driving stability, tractor semi-trailer, cross-wind, digital simulation analysis,
critical vehicle speed and critical wind speed