What is the total stopping distance at 55 mph?

The total stopping distance at 55 mph is approximately 419 feet. This total stopping distance is calculated by considering three key components: perception time, reaction time, and braking distance.

When driving at higher speeds, such as 55 mph, the distance you cover while reacting to a hazard increases significantly. The perception time is the time it takes for a driver to recognize a hazard, and the reaction time is how long it takes to apply the brakes once the hazard is identified. Combined, these times add to the distance traveled during that period.

Once the brakes are applied, the braking distance comes into play, which is the distance a vehicle travels while coming to a stop. This distance increases with speed due to the physics of stopping—specifically, the fact that stopping distance increases with the square of the speed.

At 55 mph, the formula accounts for all these distances and averages out to about 419 feet. Understanding these components highlights the importance of maintaining a safe following distance and being aware of conditions that may require a longer stop distance, such as adverse weather or road conditions.