Being tailgated is an uncomfortable experience, but it also highlights a common and often overlooked issue: many drivers fail to leave sufficient space between their vehicle and the one in front.
Understanding safe stopping distances is therefore not just a matter of comfort, but a vital part of road safety. Taking a moment to refresh your knowledge can make a significant difference when it matters most.
The key benefits of leaving enough distance between you and the vehicle ahead are:
- A better view of the road ahead
- More distance (time) to think and brake if you need to
- Reduced fuel consumption thanks to gentler braking and smoother driving
Stopping distance explained
Your stopping distance is the time it takes to react to a hazard (thinking distance) plus the time it takes to stop your vehicle (braking distance).
- Stopping distance = thinking distance + braking distance
Stopping distance and driving speed
The required stopping distance increases the faster that the vehicle is travelling.
For example, for a car, the stopping distance at 30mph, in normal driving conditions is 23 metres (or 75 foot). In comparison, for a car travelling at 70mph in normal conditions, the required stopping distance increases to 96 metres (315 foot).
This sharp rise reinforces why leaving a safe stopping distance is essential at higher speeds.
Stopping distances for cars: What are the stopping distances?
The official stopping distances for cars, as per the Highway Code are as follows:
| Speed | Stopping Distance |
| 20 mph | 12 metres (40 foot) |
| 30 mph | 23 metres (75 foot) |
| 40 mph | 36 metres (118 foot) |
| 50 mph | 53 metres (175 foot) |
| 60 mph | 73 metres (240 foot) |
| 70 mph | 96 metres (315 foot) |
Weather and stopping distance
Stopping distance is affected not only by speed, but also by weather conditions. In wet or icy conditions, tyres have less grip on the road surface, significantly increasing braking distances.
The Highway Code advises your total stopping distance in wet conditions will be at least double the distance it takes to stop on a dry surface, and 10 times more in snow and ice! This highlights the importance of accounting for wet road braking distance and adjusting your driving accordingly.
Thinking distance explained
This is how long it takes to spot a hazard before applying the brakes.
If there are only a few metres between you and the vehicle ahead, you will probably struggle to stop in time - particularly if the vehicle ahead brakes suddenly.
The Highway Code states that drivers have a thinking time of 0.7 seconds.
The higher your speed, the further you'll go in that time.
The thinking distance can be affected (increased) by:
- Drinking alcohol and drug use (slows your reaction times)
- Distractions such as mobile phones (it is illegal to use a mobile while driving)
- Fatigue (concentration levels decrease after 2 hours of driving; take regular breaks on long-distance journeys)
Braking distance
The braking distance refers to how far your car travels whilst braking, in an attempt to bring your car to an emergency stop.
What are the braking distances of a car?
Speed | Braking distance |
20mph | 6 metres |
30mph | 14 metres |
40mph | 24 metres |
50mph | 38 metres |
60mph | 55 metres |
70mph | 75 metres |
What conditions increase overall stopping distance?
Understanding these factors helps reduce tailgating risks and reinforces the importance of keeping a safe distance while driving, whatever the conditions.
- Brake condition: ensure brakes are in good working order.
- Suspension: Worn suspension can increase braking distance since weight transfer impacts braking effectiveness.
- Weight: heavier cars will take longer to stop.
- Tyres: Those with a high wet grip rating will perform better in the wet (they are rated from A - best to G - worst). Tyres with worn treads will result in an increased braking distance. Tyres should be inflated according to the manufacturer's guidelines (not under- or over-inflated, since this will increase stopping distances).
- Weather: It takes longer to stop on wet or icy roads. Double the gap if it's wet and increase the gap by up to 10 times if it is icy.
- Condition of the road: muddy or damaged roads may increase braking distances, so leave extra space between your vehicle and the one ahead.
The 2-second rule
As a rule of thumb, there should be 2 seconds between you and the vehicle ahead to keep at a safe distance. This gap should be increased in poor weather to account for reduced grip and longer wet road braking distance.
How to implement the 2-second rule
- Locate a fixed point on the road ahead, such as a lamppost.
- Look to see when the vehicle ahead passes that point.
- Ensure at least 2 seconds have passed before you reach the same point.
Want to improve your road safety knowledge and reduce the risks of driving too close?
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