How does vehicle weight affect stopping distance?

• A. Fully loaded trucks take longer to stop
• B. Fully loaded trucks stop faster
• C. Weight has no effect on stopping distance
• D. Stops are the same on dry and wet roads

Answer: (A)

Weight affects stopping distance because you have to dissipate more kinetic energy when stopping a heavier vehicle. At the same speed, a fully loaded truck carries more energy to shed, so the brakes must work longer to bring it to a halt. The brakes and tires provide a finite stopping force limited by tire-road friction, and heat can reduce braking efficiency for heavy loads. Because more energy needs to be removed and the braking system can fade with heat, a fully loaded truck generally takes longer to stop than an unloaded one, with the effect more noticeable on wet or slick roads.