Colorado CDL Practice Test

What is the average braking distance at 55 mph?

1. 150 feet

2. 200 feet

3. 216 feet

4. 300 feet

The correct answer is: 216 feet

The average braking distance at 55 mph is approximately 216 feet, which is calculated based on several factors, including vehicle speed, weight, and road conditions. At higher speeds, vehicles require a longer distance to come to a complete stop due to the physics of motion that dictate that the stopping distance increases as speed increases. When a vehicle is traveling at 55 mph, the kinetic energy it has is significantly influenced by its speed, and the brakes must overcome this energy to stop the vehicle. The formula typically used for calculating braking distance involves factors such as the speed of the vehicle, acceleration (deceleration in this case), and the friction between the tires and the road surface. At this speed, conditions such as road quality, weather, and the condition of the tires can all affect the actual stopping distance. However, the average calculated figure provides a useful benchmark for drivers to understand the minimum distance they should allow for stopping safely. Thus, understanding that 216 feet is a generally accepted average for this speed helps drivers plan for safe following distances and stopping distances in various driving conditions.