Virginia CDL General Knowledge Practice Test

The approximate stopping distance of a vehicle traveling at 55 mph under ideal conditions is indeed around 228 feet. This distance encompasses several factors critical to understanding how braking works, such as perception time, reaction time, and braking distance. At 55 mph, a vehicle covers about 80.67 feet per second. The total stopping distance includes the distance traveled during the driver's perception (roughly 1.5 seconds) and reaction time (approximately 0.75 seconds), which together account for approximately 120 feet. Once the brake is applied, the vehicle also requires additional distance to come to a complete stop due to the physics of deceleration, which in ideal conditions typically adds around 108 feet for the braking distance itself. When all these components are summed, 120 feet (perception and reaction) plus about 108 feet (braking distance) gives us the total stopping distance close to 228 feet under favorable conditions, such as a dry road and properly functioning brakes. Understanding this figure is crucial for drivers to maintain safe distances and react appropriately in various driving situations.