A fully loaded tractor trailer going 55 mph needs how many times more stopping distance than a car?

A fully loaded tractor trailer going 55 mph needs how many times more stopping distance than a car?

• A. 2x
• B. 3x
• C. 4x
• D. 5x

Answer: (B)

Stopping distance grows with how much kinetic energy the vehicle has to shed, not just with speed. A fully loaded tractor-trailer carries far more energy than a typical car at the same speed, so the brakes must dissipate a lot more energy to bring it to a stop. Even with strong braking, that extra energy means the truck needs noticeably more distance to stop—roughly three times as far as a car at the same speed. So at 55 mph, you should expect the loaded truck to need about three times the stopping distance of a car, and you should keep much more following distance behind trucks for safety.

Stopping distance grows with how much kinetic energy the vehicle has to shed, not just with speed. A fully loaded tractor-trailer carries far more energy than a typical car at the same speed, so the brakes must dissipate a lot more energy to bring it to a stop. Even with strong braking, that extra energy means the truck needs noticeably more distance to stop—roughly three times as far as a car at the same speed. So at 55 mph, you should expect the loaded truck to need about three times the stopping distance of a car, and you should keep much more following distance behind trucks for safety.