The ratio describing how much longer the braking distance is for a tractor-trailer compared to a car is:

• A. One time
• B. Two times
• C. Three times
• D. Four times

Answer: (B)

When you compare braking distances, heavier vehicles carry much more kinetic energy at the same speed, and the brakes can only dissipate that energy at a limited rate. Because of that extra energy and the limits of braking force, a tractor-trailer generally takes longer to stop than a car hitting the brakes from the same speed. The typical, easy-to-use rule is that the tractor-trailer needs about twice as long to stop as a car. That’s why you should leave a noticeably larger following distance when behind a big truck.

The other possibilities would imply the stopping distance is the same, or drastically longer, which doesn’t match how braking works in practice for a fully loaded truck versus an automobile under normal conditions.