Driving on wet roads

Don't do this!

In wet weather there is less grip available, it takes longer to stop and and you have less grip in the corners increasing the likelihood of skidding. It can take around twice as long to stop in the wet as in the dry – but this is only a guide – roads that have been dry for a while will have a build up of oil and brake dust that will make them especially slippery at first.



Also, tyres with less tread will take even longer to stop. Although the legal limit for tyre tread depth is 1.6mm, once a tyre gets below 3mm stopping distances will start increasing considerably. (A new tyre will have around 8mm of tread).


In order to stay safe in the wet, you should allow more time to stop – increase the distance between yourself and vehicles you are following by at least twice as much as usual (keep at least a 2 second gap in the dry and a 4 second gap in the wet, as an absolute minimum). Reduce your speed earlier and slower than usual whenever you may have to stop, for example approaching a junction, or when there is a risk of pedestrians stepping out.


You should reduce your speed when taking bends and corners, but aim to be slow enough to ease off the brake before you start turning, turn in smoothly and keep acceleration to a minimum until you straighten the wheels up. This way you will reduce the chance of skidding. The same is true on roundabouts which can be particularly dangerous in the wet. If you feel the wheels starting to slip, ease gently off the throttle and gently remove some steering – don’t panic, don’t lift off the gas suddenly and don’t jump on the brake or you will make things worse.


It is important to look ahead for puddles and patches of standing water which if driven into too fast can cause you to lose control – hitting the water with just one side of the car can force the car to swerve out of control. You should endeavour to slow down before hitting the water but do NOT steer or brake as you go through the water as you could lose control. If all four wheels hit the water there is a high risk of aquaplaning. This occurs when there is more water under the tyre than the tread can cope with and the tyre loses contact with the road surface, and can be detected by the sudden lightness of the steering. If this occurs , it is vital than you do not panic – simply ease the throttle up gently, hold the steering wheel firmly to stop the wheels turning and do not brake. Gradually your speed will reduce and you will regain grip as you slow down and/or reach the other side of the water.


Driving through puddles and standing water can also make the car breakdown if water gets into the engine bay. Drivers should also consider other road users who may also be trying to avoid the water, and avoid splashing pedestrians and cyclists which is not only extremely inconsiderate, but can result in points on your licence and a fine of several thousand pounds.


Visibility is another important safety factor in wet weather – you should be able to see and to be seen. Use dipped headlights, whenever it is raining or even overcast, to help other drivers to see you, and be sure to use your ventilation controls, demister, windscreen wipers and washers as necessary to give you the clearest view of the road. Also consider winding side windows down and up to clear them of rain when necessary.


Flooded roads can be an issue with very heavy or persistant rain, or from melting snow. It is important you spot a flooded road before it’s too late, slow right down and be ready to stop if you are uncertain how deep the water is. If in doubt, turn around and find an alternative route.


If you are sure the water is not too deep then drive through – keep the car very slow to avoid making waves. If the water level is above the level of the exhaust water could be sucked into the engine – to avoid this keep the car in 1st gear and maintain constant revs to keep gas passing out of the exhaust. If you lift off the throttle water could be sucked in, so use the clutch to control your speed and do not lift off the throttle until you are clear of the water. If water will be above the height of the air intake at the front of the car then it will not be possible to drive through.


When driving through a flooded stretch of road, look for the shallowest part, often in the middle of the road, and do so when there is no oncoming traffic coming through.
Finally, when you are through the water, dry and test your brakes by gently applying them when it is safe to do so (check for following vehicles first).


Spray can also affect visibility, so anticipate this near other vehicles, particularly large vehicles like lorries. Turn your wipers up to a faster setting before being affected and slow down further if necessary.


Modern cars insulate us from what is going on outside, so unless you have ever lost control in the wet, it is hard to understand how quickly or how badly things can go wrong. Do respect wet roads, but if you follow the advice above you have a very good chance of staying safe.