How do Weather Conditions affect Stopping Distances?

Stopping distance is calculated by adding your thinking distance (the time it takes for the driver to realise they need to stop) and braking distance (the time between the driver applying the brake and for the car to come to a halt). The Highway Code sets out a minimum stopping distance which is considered safe. However, this distance will be affected by multiple factors, including your tyres, how fast you are travelling and the weather conditions you are driving in.

Having said this, it’s important for all drivers, novice or experienced, to understand how stopping distances can be affected by these factors. While weather shouldn’t affect your thinking distance, your braking distance will be massively impacted by the road conditions, and as a general rule of thumb, the worse the conditions, the longer the stopping distance. 

We’ve put together a simple guide so you can drive (and stop) safely, whatever the weather.

Stopping Distances made Simple

The Highway Code’s average stopping distance is calculated in normal driving conditions. These are as follows:

30mph – 14m

40mph – 24m

50mph – 38m

60mph – 55m

70mph – 75m

If you have trouble remembering the different stopping distances, it is generally recommended to leave a 2 second gap between you and the driver in front. This gap will generally give you enough time to come to a halt in the case of an emergency.

Rain

Wet roads and heavy rain can affect both visibility and stopping distances. It’s recommended to pay extra care to your surroundings when driving in these conditions. Braking distances generally double in wet conditions, so as to ensure safe stopping with enough distance between you and the vehicle in front, make sure to keep a larger gap.

Surface water can cause a car to aquaplane and make the driver lose some control over the vehicle. It’s also important to remember that brakes become ineffective when aquaplaning and as a result, this can cause some drivers to panic. Here are some key things to remember when braking in wet weather:

Grip the steering wheel firmly and gently steer in the direction you want to go

Don’t accelerate or brake harshly

Ease off the accelerator and gently apply the brake

Fog

While road conditions may not be massively affected by fog if there is no other adverse weather, visibility is evidently reduced in mist or fog. In these conditions, drivers’ reaction times can be affected if, for example they are concentrating on their own visibility.

To accommodate for yourself and other drivers, you should make sure to double your stopping distance and keep a larger gap than usual between your car and the one in front. The main piece of advice for driving in fog is to make use of your fog lights, as they not only improve your visibility, but alert other drivers to your presence. 

Ice & Snow

Driving in wintry conditions is inherently more dangerous. If your tyres are worn or not suitable for the weather, snow and ice can become compacted in the tread and cause them to lose grip and traction on the road surface. 

When considering your stopping distance in these conditions, this should be multiplied by 10 and there should be a considerable gap between you and the car in front, to ensure a safe and steady stop.

Follow these 3 tips when driving and braking in snow or ice, or in the case of a skid:

Don’t slam the brakes

Gently steer your car in the direction of the skid

Stay in as low a gear as possible

Equip your car for the weather

As we’ve outlined, there are a number of ways stopping distances can be affected. Having the right tyres on your car can make a huge difference in helping to keep your stopping distances as low as possible. Investing in a set of new, reputable tyres from leading brands such as Goodyear, is a good starting point to safer driving and stopping in adverse weather.

Why not try a set of winter tyres in the lead up the season to tackle the impending snow and ice. The special rubber compound and optimised tread of the Ultragrip Performance Gen-1 winter tyre has improved grip on ice and snow and fares better in the cold and wet conditions than summer or all-season tyres. 

As their name suggests, all-season tyres perform proficiently all year round. They don’t have the tailored tread to improve traction on ice and snow, nor are they designed to stand hot weather so they might not appear to measure up to season specific tyres. However, the Vector 4Seasons Cargo offers good dry road grip as well as aquaplane resistance. For someone that doesn’t want to change their tyres throughout the year, all-season tyres are an ideal choice.

Browse the full range of Goodyear tyres on the Asda tyres website


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