Texas CDL General Knowledge Practice Exam

What is the typical total stopping distance needed for a vehicle driving at 55 mph on dry pavement?

1. Twice the length of a football field

2. Equal to the length of a football field

3. Shorter than the length of a football field

4. The length of a football field

The correct answer is: The length of a football field

The correct answer indicates that the typical total stopping distance for a vehicle traveling at 55 mph on dry pavement is approximately the length of a football field, which is about 120 to 130 yards. At this speed, a driver needs to account for the perception distance, reaction distance, and braking distance. Perception distance refers to the length of road a vehicle covers while the driver identifies a hazard. Reaction distance is the distance covered while the driver reacts to the hazard by moving their foot from the accelerator to the brake. Finally, braking distance involves the distance it takes for the vehicle to come to a complete stop once the brakes are applied. When these components are added together, the total stopping distance can easily approach or exceed the length of a football field at that speed. This highlights the importance of maintaining a safe following distance and being aware of stopping capabilities, especially at higher speeds.