How Speed Affects Braking Distance

Types of Distances

A lot of different factors can affect your braking distance. Braking distance is a measurement of how far your vehicle travels during the time it takes to come to a complete stop once you hit the brakes. Your braking distance will be shorter (aka better) if your brakes and tires are in good condition. That means you should make sure your tires have the right air pressure level and plenty of tread.

No matter how nice or well cared for your vehicle is, the best indication of your braking distance will be your speed. Watch how a vehicle’s speed changes its braking distance.

Thinking Distance

Thinking distance is the amount of time it takes for you to decide to hit the brakes, and then actually hit them. When you see a potential threat, sign, or traffic control on the road, you don’t break instantaneously. You may need a second or two to move your foot to the brake pedal. Reaction time can be slowed down if the driver is sleepy, sick, impaired, or distracted. Make sure you’re sober and alert every time you drive because sometimes an extra second can make all the difference.

Braking Distance

Braking distance is the time it takes for your car to come to a complete stop after you've hit your brakes. When you double the speed of your car, your braking distance quadruples. As shown below, every time you double your speed, you multiply your braking distance by four. This piece of information will be important for determining your total stopping distance. Keep reading!

Total Stopping Distance

The equation for figuring out how far your car will go from the moment you see a hazard to the moment you’re completely stopped is:

> [thinking distance] + [braking distance] = [total stopping distance]

The faster you’re driving, the more ground you’ll cover as you react and start braking. That makes sense, right? Check out the total stopping distance equations below for vehicles driving at various speeds.

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60 mph: Thinking Distance of 60 feet + Braking Distance of 180 feet = Total Distance of 240 feet

40 mph: Thinking Distance of 40 feet + Braking Distance of 80 feet = Total Distance of 120 feet

20 mph: Thinking Distance of 20 feet + Braking Distance of 20 feet = Total Distance of 40 feet