4.2 Deceleration

Deceleration, or braking, is largely a function of braking technology (e.g., drum brakes versus disc brakes), weight distribution across the braking axles, and height of the vehicle’s center of gravity. Generally, the braking performance for tractor-trailers is much poorer than that for passenger vehicles. This is because of the tractor-trailer’s high center of gravity, the greater difficulty of achieving optimal weight distribution relative to the braking axles, and relatively poor braking mechanical efficiency. The latter issue is a result of the large and challenging axle configuration of tractor-trailers.