In case you must reverse your vehicle, using driver’s side backing:

Back toward the driver’s side so you can see better. Backing toward the right side is very dangerous because you cannot see as well. If you back and turn toward the driver’s side, you can watch the rear of your vehicle by looking out the side window. Use driver-side backing—even if it means going around the block to put your vehicle in this position. The added safety is worth it. [Commercial Driver Handbook]