Wet weather stopping distances: what you need to know

Stopping in wet weather

How long would it take your car to stop in an emergency? Clue: it's probably longer than you think. And as 2019 takes an icy turn – snow is forecast soon – you need to make sure you stay safe on roads where stopping might become significantly more hazardous.

What is stopping distance?

First of all: your car's stopping distance is not the distance it travels after you apply the brake. That is your braking distance. Your total stopping distance also includes your thinking distance – the distance you travel while your brain reacts to a hazard and tells your foot to press the brake.

Yes, yes, we are sure all our readers are extremely clever, but cars also travel very fast. At 70mph, you could cover the length of four cars before you apply the brakes.

The Highway Code gives the thinking and braking distances below for an average family car. Bigger, heavier cars, people carriers and 4x4s will take longer to stop, as will cars carrying a lot of passengers or luggage. Bear all this in mind when deciding how much space you need to leave behind the car in front.

SpeedThinking distanceBraking distance Total

20mph6m6m12m

30mph9m14m 23m

40mph12m 24m 36m

50mph15m 38m 53m

60mph18m 55m 73m

70mph21m 75m 96m

What factors affect stopping distances?

Weather: Stopping distances in bad weather conditions can be much longer. Braking distances can double on wet roads – and increase tenfold on snow or ice. It could take a car more than the length of seven football pitches to stop from 70mph on icy roads. Poor visibility might make this even worse, as you may not see and react to hazards immediately. And remember that you can't see black ice.

You: Your reaction times will be slower if you are tired or distracted or have been drinking, even if you're under the limit.

Tyres: Damage, under-inflation or insufficient tread on your tyres will reduce your car’s ability to brake. The RAC says that tyres right on the legal tread limit of 1.6mm can add another 60 per cent to your braking distance compared to brand new tyres.

In the UK, most drivers use summer tyres all year round, but many dealers and car maintenance providers recommend changing to winter tyres whenever it gets below 7°C to help you stop more quickly. That’s because winter tyres are made from different compounds and are optimised to perform better at lower temperatures. Don't keep winter tyres on above 7°C though, as they will then work less well than your normal tyres.

At Carwise Group, we have a huge range of reliable used cars of a variety of makes and models for sale – and they're all thoroughly inspected by our in-house technicians. If you'd like to test drive one of them, call us at whichever of our dealerships is most convenient for you – you'll find us in Dunstable, Harlow and Maidstone.