Colorado CDL Practice Test

What formula describes total stopping distance?

1. Perception distance + reaction distance

2. Perception distance + braking distance

3. Braking distance + reaction distance

4. Perception distance + reaction distance + braking distance

The correct answer is: Perception distance + reaction distance + braking distance

Total stopping distance is the overall distance that a vehicle travels from the moment a driver first perceives a hazard until the vehicle comes to a complete stop. This distance is made up of several components: perception distance, reaction distance, and braking distance. Perception distance refers to the distance a vehicle travels while the driver is recognizing a hazard. This is crucial because it measures the time it takes for the driver to notice something that requires action, such as an obstruction in the road. Reaction distance is the distance a vehicle covers during the time it takes for the driver to physically respond after perceiving the hazard. This includes the moment the driver decides to actuate the brakes until the brakes actually start to apply. Braking distance is the distance covered by the vehicle while the brakes are being applied until the vehicle comes to a stop. This distance is influenced by factors such as the speed of the vehicle, road conditions, and the efficiency of the braking system. Since all three components contribute to the total stopping distance, the correct formula to describe total stopping distance is the sum of perception distance, reaction distance, and braking distance. Understanding this concept is essential for safe driving and for being aware of how long it takes to stop under various conditions.