Stopping Distances In The Wet

Adhering to the appropriate stopping distances is essential to to ensure driver safety, but beyond the learner driver’s theory test, many of us tend to forget. Whether you’ve been driving for years or your children have just started driving, knowing everything there is about your stopping distances is crucial.

When you spend a lot of time on the road you are exposed to so many variables. We see dangers on the roads every day, including tailgating where people follow too closely to other cars. It is one of the biggest causes of road accidents in the UK and could also result in failing your driving test.

Thinking Distance And Braking Distance

According to the Highway Code, the definition of “Stopping distance” consists of two parts. Firstly, there is the “thinking distance” or the time it takes for the driver to react to a certain situation requiring. Secondly, there is the actual “braking distance” or the length your car travels after applying the brakes until it comes to a complete stop.

The following table is based on Highway Code findings and provides thinking distances at different speeds.

SpeedThinking distance(before reacting)
20mph6 metres
30mph9 metres
40mph12 metres
50mph15 metres
60mph18 metres
70mph21 metres

The next table indicates official braking distances provided by the Highway Code. This shows how far your car will travel while your foot is on the brake attempting to make an emergency stop.

SpeedBreaking Distance
20mph6 metres
30mph14 metres
40mph24 metres
50mph38 metres
60mph55 metres
70mph75 metres

Regardless of driving in town, on the motorway or country roads, when you need to stop you must do so as safely and as quickly as possible. It is important to realise that braking distances can often double when driving in wet conditions, therefore drivers need to pay attention to the road and ensure that their tyres are well maintained. Many drivers don’t realise just how important their tyres are especially in wet conditions.

Do Premium Tyres Provide Better Stopping Distances?

By now you should know that the legal tyre tread depth is 1.6 mm and as the tread wears, the ability to grip the road reduces considerably. It only gets worse when driving in the wet, putting you, your family and other road users at risk. Tyre tread directly affects how your car grips the road as the tyre tread expels water in wet driving conditions.

In addition to the tyre tread, under-inflated tyres make it harder to safely control your car since they cannot effectively grip the road surface. Over-inflated tyres are just as dangerous as they literally reduce the area of the tyre that makes contact with the road surface which results in less grip. If you want to learn more about tyre safety, read this article on about 5 Things You Never Knew About Your Tyres.

Tyre labels indicate different classes of tyres and are categorised in seven classes. In terms of wet braking performance, A-rated tyres will have the shortest stopping distances on wet roads compared to a G-rated tyre which has the longest braking distances.

Did you know that driving at 50 mph on A-rated tyres can help you stop up to 18m* shorter? That is approximately 4 car lengths sooner than if you were driving on G-rated tyres (Source: European Commission impact assessment SEC (2008) 2860).

* This data was measured according to the test methods set out in Regulation EC 1222/2009.

It’s important to choose your tyres according to your driving requirements. If you consistently drive in wet conditions, you are better off buying A-rated tyres to maximise the safety of you and your family.

5 Important Factors That Also Affect Stopping Distances

As we mentioned earlier, there are a number of factors that can affect stopping distances besides travelling at high speed and tyre quality.

Check Your Brakes

While modern technology like ABS (anti-lock braking system) can certainly help with braking distance, it doesn’t do anything in terms of thinking distance. Of course, things might be different if the car is fitted with an automatic emergency braking system, synonymous with self-driving technologies.

For now, you should focus on regular brake checks and maintenance which will ultimately help reduce stopping distances. Brake pads can wear quickly and before you know it, grooves have formed which could cause them to overheat and underperform.

Road and Weather Conditions

There is a lot of things we can control but the weather is not one of them. Standing water, ice and snow can have a massive impact on stopping distances regardless of tyre quality. Heavy rain can cause aquaplaning where your tyres cannot disperse the water between the tread and the road surface fast enough and often results in losing control. Snow can also be a big problem as it gets compacted in the tyre tread making it difficult to find grip.

Visibility

Visibility may not affect stopping distances but it certainly does impact on your thinking distance. If you see a potential road hazard at the last minute, you will have less time to safely apply the brakes. Make sure your windscreen is clean, top up your fluids and check that your wipers are in good condition. Also, don’t forget to demist your windows before setting off as it will be hazardous to drive off with limited visibility.

Alcohol And Drugs

We have all seen the countless road awareness campaigns and heard too many tragic stories. Alcohol and drugs, including cannabis and cocaine, can greatly increase the time it takes to process important information. It could take drivers a few extra vital seconds to identify a possible hazard before applying the brakes. Recent evidence also suggests that intoxicated drivers don’t press the brake pedal hard enough in an emergency stop situation as their senses are impaired.

Driver Tiredness

Many people may associate driver tiredness with long distance motorway driving but it can happen anywhere and at any time. As many as one in five motorway accidents occur as a result of drivers falling asleep behind the wheel. Even if you don’t fall asleep, driving while tired really slows down your reaction time and decision making abilities. If you get tired or start losing concentration while driving, find a safe place to pull over and take a break. On long journeys, you should take a 15-minute break every two hours and share driving duties if you can.

Regardless of the car you drive or experience behind the wheel, anything can happen and its best to prepare for the worst. If you are concerned in any way about the condition of your tyres, don’t waste another second, book a free tyre check with Elite Garages today. Our expert technicians are here to help you and your family with professional and friendly advice.

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