Stopping distance and braking distance
The distance after which you stop is sometimes shorter or longer than at other times. This is due to the following factors:
- The speed at which you are driving. The higher your speed, the longer your stopping distance will be. If you double your speed, the braking distance increases quadratically. The braking distance then becomes four times longer. For example, if the braking distance at 50 km/h is 20 meters, the braking distance at 100 km/h will be 80 meters.
- What type of road surface? On an asphalt surface, your braking distance will be shorter than on a paved surface.
- What is the condition of the road surface? Is it dry, wet, or covered in sand and mud? Your stopping distance will vary each time.
- What is the condition of your vehicle? Specifically, the condition of the tires, brakes, and suspension.
- How hard are you braking? You brake harder at some times than at others. Braking force is expressed in m/s². Braking at 8 m/s² has a shorter braking distance than braking at 5 m/s².
- Are you driving alone, or with passengers and luggage? If you’re driving alone, the braking distance is shorter than if you’re carrying many passengers and luggage.
- Reaction time. The time it takes you to actually brake after seeing something is called reaction time. If you’re well-rested, your reaction time is significantly shorter than when you’re tired or under the influence of alcohol, drugs, or medication. The average reaction time is about 1 second.
Braking distance is the distance a vehicle travels from the moment it brakes. Braking distance depends on the initial speed and the brake deceleration.
Braking distance can be calculated by dividing the square of the speed, in meters per second, by twice the brake deceleration, in meters per second².
Stopping distance is the distance a vehicle needs to come to a stop from the moment the driver perceives a hazard. During the reaction time, the car continues to drive normally. This distance is called the reaction time. The reaction time is on average 1 second.
The reaction time and braking distance together form the stopping distance.
