Master Driver Qualification 022-26 Practice Exam

The main idea is that wheel chocks prevent any parked vehicle from moving by blocking forward and backward motion. When parking a tractor-trailer on level ground, you place chocks against the wheels that could move on both sides of those tires and position them in front of and behind them. This setup stops movement in either direction, which is important because even on level ground a vehicle can creep due to wind, small slopes, or brake release. Using chocks on only one side or only in front of or behind the wheels isn’t enough to stop movement, and not using chocks at all on level ground is unsafe.