Braking Distance | Stopping Distance Formula

Braking - Florida Permit Test

Learn about braking distance, total braking distance, and smooth stops.

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Proper braking is a critical part of being a safe driver.

Learning a few things about using your brakes will make you a safer driver and help you pass the Permit Test to get your Florida Learners Permit.

Once you have watched the videos and read the guides below on Braking, Braking Distance and How your Speed Affects you Ability to Stop we recommend you take our practice test on Braking to determine if you understand the topic.

Braking and Braking Distance Topics

Two factors that effect your braking distance are Perception and Reaction times.

Perception is when you see a hazard and recognize that you have to stop and Reaction is how long it takes you to hit the brakes. These two factors each add a delay to the braking process.

Below are the time and distance increases in braking caused by perception and reaction at 50 mph.

  • Perception time = 3/4 of a second to 1 second.
  • Perception distance = 55 feet.
  • Reaction time = 3/4 of a second to 1 second.
  • Reaction distance = 55 feet.

The perception and reaction distance together add up to 110 feet to your total stopping distance - this does not include actual braking distance.

The faster you drive the longer it takes to stop. This means speeding increases your stopping distance and force of impact.

How Speed Effects Stopping Distance and Impact

Double your speed from 20 to 40 mph your braking distance and force of impact are 4 times greater.

Triple your speed from 20 to 60 mph and your braking distance and impact are 9 times greater.

Quadruple your speed from 20 to 80 mph and your braking distance and impact are 16 times greater.

The increases in braking distance and force of impact are one of the reasons that speeding is so dangerous.

Total stopping distance is not as simple as how long your car takes to stop once you hit the brakes.

At 50 mph, your total stopping distance is at least 268 feet.

The 268 feet is the combination of:

  • 55 Feet for Perception.
  • 55 Feet for Reaction.
  • 158 feet for Braking.

The stopping distance is based on ideal conditions with brakes in good condition. If it's raining or dark, for example, total stopping distance will increase.

Making smooth stops - not slamming on your brakes - is important because it will help to avoid rear end collisions and keep your car under control as you turn.

Here are steps to follow for smooth, safe stops:

  1. Check your mirrors and blind spots before you stop.
  2. Take your foot off the gas pedal so you car will start to slow down.
  3. Press your brake pedal to turn on your brake lights.
  4. Use smooth steady pressure on the brake pedal.

Smooth stops are a good habit and will help you avoid getting hit by a car behind you. Smooth stops also reduce wear on your brakes.

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