Commercial Driver License (CDL) Class B Practice Test

What three components make up total stopping distance?

1. Perception distance, reaction distance, braking distance

2. Speed limit, reaction time, road conditions

3. Braking distance, driver fatigue, vehicle weight

4. Perception time, vehicle maintenance, weather conditions

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

Total stopping distance is a crucial concept for drivers to understand, especially for those operating commercial vehicles. It is made up of three key components: perception distance, reaction distance, and braking distance. Perception distance is the distance a vehicle travels from the moment a driver first sees a hazard until they comprehend the need to stop. This distance is influenced by factors such as visibility, the driver's attentiveness, and the speed of the vehicle. Reaction distance follows perception distance and accounts for the distance a vehicle covers from the time the driver decides to take action (like applying the brakes) until they physically do so. This interval can vary based on the driver's reaction time, which can be affected by factors such as fatigue, distractions, or road conditions. Lastly, braking distance is the distance a vehicle travels from the point of applying the brakes to a complete stop. This distance is dependent on factors like the vehicle's speed, the braking efficiency of the vehicle, and the road surface conditions. Together, these three components—perception distance, reaction distance, and braking distance—combine to create the total stopping distance, which is essential for maintaining safe stopping practices while driving, especially in commercial driving scenarios where larger vehicles have longer stopping distances.