Which statement about vehicle weight and stopping distance is true?

Which statement about vehicle weight and stopping distance is true?

• A. Heavier vehicles stop more quickly than lighter ones.
• B. Weight has no effect on stopping distance.
• C. Stopping distance decreases as weight increases.
• D. Heavier vehicles require longer stopping distances; space accordingly.

Answer: (D)

The main idea is that stopping distance grows with vehicle weight because heavier vehicles carry more momentum at a given speed, and braking systems have to dissipate that extra energy. At a set speed, momentum is mass times velocity. More mass means more momentum to shed, so the braking distance—the part of stopping distance that comes from slowing the vehicle down—tends to be longer. Brakes and tires can only provide a limited friction force, and weight transfer during braking changes how much grip is available on each axle. With heavier loads, that grip can be stressed more, especially on trucks, making it harder to stop quickly. So heavier vehicles generally require more distance to come to a complete stop, and you should leave more space for them. That’s why the statement about heavier vehicles needing longer stopping distances and spacing accordingly is the best choice.

The main idea is that stopping distance grows with vehicle weight because heavier vehicles carry more momentum at a given speed, and braking systems have to dissipate that extra energy.

At a set speed, momentum is mass times velocity. More mass means more momentum to shed, so the braking distance—the part of stopping distance that comes from slowing the vehicle down—tends to be longer. Brakes and tires can only provide a limited friction force, and weight transfer during braking changes how much grip is available on each axle. With heavier loads, that grip can be stressed more, especially on trucks, making it harder to stop quickly. So heavier vehicles generally require more distance to come to a complete stop, and you should leave more space for them.

That’s why the statement about heavier vehicles needing longer stopping distances and spacing accordingly is the best choice.