Newly passed, gearing up for your theory test or years of experience under your belt – drivers of all stripes should be aware of stopping distance. Not only does it play a crucial role in the safety of yourself and other road users, but it could also easily be the deciding factor in whether you pass your driving test.

However experienced you are behind the wheel, we’ve created this handy refresher to help explain what stopping distances are, the factors which can affect them, and what to think about when you need to calculate stopping distances out on the road.

What does stopping distance mean?

Stopping distance simply refers to the time taken for a moving car to come to a complete stop. It can be affected by a range of factors, including the car, the driver and the driving conditions.

In most situations, stopping distance is frequently used to describe the exact time needed to stop a vehicle in an emergency. Whether it’s when a pedestrian crosses without warning or when there’s an incident in the flow of traffic ahead – being aware of your stopping distance is vital when it comes to everyone’s safety. 

The average stopping distance of an individual car and driver is calculated by adding thinking and braking distance together. This is all well and good, but what do these two factors entail? Let’s have a look below.

What is thinking distance?

This is the distance your car travels after you’ve spotted a danger, an obstacle or an incident before you apply the brakes. This distance will obviously vary from person to person, but the average distance before a driver realises danger is ahead when travelling at 20 mph is six metres.

What is braking distance?

Braking distance is the distance your car travels after the brakes are applied. Since the average car travels six metres before coming to a complete stop when travelling at 20mph (according to the Highway Code), your stopping distance at 20mph will be 12 metres.

woman driving

What to consider when calculating stopping distance

When you’re on the road, you should always leave enough distance in front of you to be able to come to a stop at any given moment.

When it comes to remembering stopping distances as part of your theory test, it’s important not to get caught out. Luckily, there’s an easy way to remember them.

Beginning with 20 mph, simply multiply the speed by intervals of 0.5, starting with two. This will provide you with the stopping distance in feet, as follows:

  • 20mph x 2 = 40 feet
  • 30mph x 2.5 = 75 feet
  • 40mph x 3 = 120 feet
  • 50 mph x 3.5 = 175 feet
  • 60 mph x 4 = 240 feet
  • 70mph x 4.5 = 315 feet

To get the stopping distance in metres, simply divide the result by 3.3.

What affects a car’s stopping distance?

Wondering what factors affect your stopping distance on the road? Keep these in mind next time you’re behind the wheel.

The weather

A car’s stopping distance will increase in poor weather conditions. Drivers will react more slowly when visibility is poor, increasing thinking distance as a result. Throw in rainy, snowy or icy conditions, and you can expect braking distance to increase too.

In fact, it’s been shown that braking distances can double in wet conditions, while ice and snow can multiply the number up to ten times!

Volvo Service Mechanic Wheel Inspection

How to improve stopping distance

You can minimise your stopping distance – and be safer on the roads – by considering the following…

Get in the habit of servicing and checking your brakes more frequently. The condition of your car’s brakes can change a lot between annual MOT inspections, so frequent brake checks can help you pick up on issues before they impact stopping distance.

Make sure your tyres are up to the task. Before you hit the road, check your tyres are at the correct pressure and inspect the tyres’ tread. You might also consider purchasing tyres designed to function better in both summer and winter seasons for optimal performance.

Adjust your driving style for the conditions. If it’s wet, foggy or icy, leave double the space between you and the vehicle in front, and accept that the conditions will impact your journey time.

Take regular breaks to reduce tiredness and fatigue on long journeys. Remember, thinking time is one of the primary factors that can affect overall stopping distance, so you need to stay fresh and alert at the wheel. On long journeys, it’s recommended that you stop at least every two hours to maintain peak focus, so plan your route accordingly.

For more motoring tips and advice, head to the Brindley blog. In the market for a used car? Maybe you want to learn about our servicing options? Follow the links or contact your local Brindley Group dealership.