Stopping Distance, Braking Distance & Reaction Distance Explained
An important part of preventing a rear-end collision is knowing your stopping distance and how quickly your vehicle can come to a complete stop. Create a safety margin that gives sufficient distance between the vehicle in front so there is time to react and safely stop. In order to make a complete stop before a collision occurs, you must mentally calculate the stopping distance.
Knowing how speed affects the stopping distance is vital to be a safe driver. But first, let’s go through some important information.
What is Reaction Distance?
Reaction distance is the distance your vehicle travels while you react. So the time it takes from the moment you see a hazard until you actually start braking. Reaction times vary from driver to driver.
What is Braking Distance?
Braking distance is the distance that it takes your vehicle to come to a full stop starting from the moment when you start applying the brake.
What is Stopping Distance?
The stopping distance = reaction distance + braking distance. So the distance it takes for your vehicle to come to a complete stop from the moment you spot a hazard.
The Stopping Distance Formula
Speed makes a very big difference to your ability to stop in time and a significant difference to your chance of being involved in a crash:
- At 30 mph you need roughly 120 feet to come to a complete stop (65 feet to react and 55 feet to brake) in good conditions.
- At 60 mph you need roughly 360 feet to come to a complete stop (130 feet to react and 190 feet to brake) in good conditions.
Small increases in speed also affect stopping distance. Increasing your speed just 10 mph from 50 mph to 60 mph increases the total stopping distance by up to 40%.
In general, double the speed increases the braking distance four times, and triple the speed increases the braking distance by nine times.
Other Factors That Affects the Stopping Distance
- reaction time
- tire condition including tread depth and air pressure
- road conditions
- weather conditions
- vehicle’s condition and braking capacity
Dirt roads require a longer stopping distance to bring your vehicle to a complete stop
Take our full course with tests and theory
450+ exam-like questions
All you need to ace your test
Perfect for first-timers, renewals and senior citizens
Engine Braking Explained: What It Is and How to Do It
What is Engine Braking? Engine braking is the process of reducing the speed of your car by removing your foot from the accelerator pedal and shifting down through the gears. It works without ever having to engage the foot brake. When you take your foot off the accelerator, the throttle body valve closes, limiting airflow […]
What are Hazard Lights and When Should You Use Them?
Emergency lights for vehicles, often known as hazard lights, are a must-have in today’s world. The uses for them are many: you can express the urgency of your travel to other drivers, bring attention to a hazard when you’re stationary – or in the case of law enforcement, alert the driver to halt for contact […]
How to Drive in Snow and Ice: 10 Winter Driving Tips
As the days grow shorter and the weather turns cooler in much of the United States, everyone begins slowly preparing for winter weather conditions. Warmer clothes come up from the basement, fireplaces are cleaned out and prepared, and plans for the holidays begin taking shape. Before the snow falls, it’s important to review some safe […]
Ace your DMV test, guaranteed