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Writer's pictureSimon Harrison

Stopping Distances








What is stopping distance?


Stopping distance is the time that it takes to bring a moving car to a complete stop. This includes the time it takes you to react to the hazard (thinking distance), and the time it takes for the brakes to stop the car (braking distance)

You can calculate it with this stopping distance formula:

Stopping distance = thinking distance + braking distance

When driving, you should leave enough clear distance in front of you to be able to come to a stop. This is in case the traffic suddenly slows down, causing you to brake. We can achieve this by following the 2 second rule


However, stopping distances vary depending on factors like the weather and your driving speed.


Stopping distances

Stopping distances include the distance travelled while the driver notices a hazard and applies the brakes (thinking distance), and while the vehicle comes to a full stop from its initial speed (braking distance). The government’s official estimates of stopping distances for cars are shown below. SpeedThinking + braking distanceStopping distance20mph6m + 6m12m (40 feet)30mph9m + 14m23m (75 feet)40mph12m + 24m36m (118 feet)50mph15m + 38m53m (174 feet)60mph18m + 55m73m (240 feet)70mph21m + 75m96m (315 feet)

The distances above are based on a reaction time of 0.67 seconds, which assumes the driver is alert, concentrating and not impaired. Driving when tired, distracted or impaired significantly increases reaction times, so the thinking distances above should be regarded as minimums.

The braking distance depends on how fast the vehicle was travelling before the brakes were applied, and is proportional to the square of the initial speed. That means even small increases in speed mean significantly longer braking distances. Braking distances are much longer for larger and heavier vehicles, and in wet or icy conditions, so again these figures are a minimum.

Technology such as anti-lock brakes and stability control are designed to enable greater control over the vehicle, not shorten stopping distances. There may be a very small reduction in braking distance with modern technology, but not enough to significantly affect your overall stopping distance.

Whatever technology a vehicle has, the basic fact remains that the faster you drive, the longer your stopping distance, and therefore the less chance you have of stopping in time in an emergency.



If you are interested in learning to drive then please call Simon at 4front Driving School on 07905657229

Or visit our website on http://www.4frontdrivingschool.co.uk

You can email 4frontdrivingschool@gmail.com

Or visit our Facebook Page at http://www.facebook.com/4frontdrivingschool

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