Virginia CDL General Knowledge Practice Test

Higher speeds result in longer stopping distances due to the physics of motion and the relationship between speed and the time and distance needed to come to a complete stop. When a vehicle is traveling at a higher speed, the momentum increases, which means that more energy is present. To bring the vehicle to a stop, the brakes must overcome this increased momentum, requiring more time and distance.

The stopping distance is comprised of two main components: the perception/reaction distance and the braking distance. As speed increases, both of these distances also tend to increase. The time it takes a driver to perceive a hazard and react adds to the overall stopping distance, and this reaction time becomes more significant at higher speeds. Additionally, higher speeds lead to longer braking distances due to the greater distance required for the vehicle to decelerate to a stop, illustrating a quadratic relationship where doubling the speed can more than double the stopping distance.

Understanding this relationship is crucial for safe driving practices, as it emphasizes the importance of adjusting speed based on road conditions, vehicle load, and visibility to ensure drivers can stop safely when needed.