What are the correct UK stopping distances?

An essential part of being a safe driver is understanding and calculating the correct stopping distances. At some point, you may have experienced getting too close to another vehicle while driving, known as tailgating, which is illegal in the UK.

Merityre’s helpful guide covers what you need to know about the correct stopping distances in the UK.

What is stopping distance?

Stopping distance is the total amount of time your vehicle takes to stop. The stopping distance can be affected by your reaction time, the condition of your vehicle’s braking system, the weather and driving conditions. Typically, the stopping distance is calculated using the following formula:

Thinking Distance + Braking Distance = Stopping Distance

What is thinking distance?

Thinking distance is defined as the distance travelled in the time taken to activate the car’s brakes to avoid the hazards ahead of you. If the vehicle ahead of you suddenly brakes, the thinking distance would be calculated from the car in front braking to when you start to brake. According to the UK Highway Code, the thinking distance for an average vehicle (of approximately 4 m in length) would be calculated like this:

Source: RAC

What is braking distance?

The braking distance starts when you apply the brakes and ends when you come to a stop or take your foot off the brake pedal. Typically, the braking distance would begin from the second you apply the brakes to the second you stop. The Highway Code sets out braking distances, based on a 4m car:

Source: RAC

How do I calculate my vehicle’s stopping distance?

Our stopping distance calculations below are based on an average family-sized vehicle driven by an attentive driver in good weather conditions.

Multiply the first 20 mph by 2 to calculate your stopping distance in feet (40 feet). For every additional 10mph, add 0.5 to the multiplier, as seen here:

•  20 mph x 2 = 40 feet (12 metres or 3 car lengths)
• 30 mph x 2.5 = 75 feet (23 metres or 6 car lengths)
• 40 mph x 3 = 120 feet (36.5 metres or 9 car lengths)
• 50 mph x 3.5 = 175 feet (53 metres or 13 car lengths)
• 60 mph x 4 = 240 feet (73 metres or 18 car lengths)
• 70 mph x 4.5 = 315 feet (96 metres or 24 car lengths)

What can affect stopping distance?

Stopping distance can be affected by many factors every time you drive your car:

• The weather can increase your vehicle’s stopping time, creating the potential for more accidents. In wet or icy conditions, your car’s stopping distance can double due to reduced grip on the slippery road surface. Meanwhile, sunny weather can reduce visibility as the sun could temporarily blind you, making it harder to see and react to upcoming hazards.
• Road conditions play a significant impact on stopping distances. Hot weather can create greasy roads, increasing your stopping distance. Knowing the road conditions you are driving on, is essential for understanding the gap you need to leave from the car in front.

How to reduce your stopping distance

There are things you can do to reduce your car’s stopping distance:

• Not driving under the influence of alcohol and drugs.
• Don’t drive when you are tired or ill.
• Regularly checking your car’s condition – worn brake pads or tyres can increase your stopping distance.
• Don't be distracted by using your mobile phone or satellite navigation system while driving.

Knowing the correct stopping distances ensures you avoid tailgating other drivers and ensures you avoid being involved in an accident. Are you looking to decrease your vehicle’s stopping distance? Replace your brakes with new ones with our friendly brake experts by visiting your local Merityre branch today.