If you are braking on dry pavement while traveling at 55 mph, how much distance will brake lag add to your overall stopping distance?
Answers
32 feet
45 feet
20 feet
The Correct Answer and Explanation is :
The correct answer is 32 feet.
Explanation:
When you apply the brakes while traveling at 55 mph on dry pavement, the vehicle will experience brake lag. Brake lag refers to the delay between the time you press the brake pedal and the time the brakes actually begin to slow the vehicle. This delay occurs due to mechanical factors like hydraulic systems and the time it takes for the driver to react and apply the brakes. In real-world conditions, it is important to account for this lag in stopping distance calculations.
The overall stopping distance of a vehicle is the sum of two main components:
- Perception Distance: The distance the vehicle travels while the driver identifies the need to stop.
- Reaction Distance: The distance the vehicle travels while the driver reacts and begins braking.
- Braking Distance: The distance the vehicle travels after the brakes are applied until it comes to a complete stop.
Brake lag specifically affects the reaction distance, which occurs during the time between applying the brakes and the brakes engaging. On dry pavement, at a speed of 55 mph, the brake lag adds approximately 32 feet to the total stopping distance.
This addition to the overall stopping distance can be calculated based on the typical braking lag time of around 0.5 seconds. Since the vehicle is traveling at 55 mph (which is about 80 feet per second), during the brake lag period, the vehicle will cover around 32 feet (0.5 seconds × 80 feet per second).
This means that, although the brakes may be fully applied, the vehicle continues to move for about 32 feet before the braking force begins to slow it down effectively. As a result, the vehicle’s total stopping distance will be longer than the braking distance alone, with brake lag being a crucial factor to consider for safety in emergency stopping situations.