When driving in the rain or when the road is wet, your ability to stop is reduced. In such conditions stopping distance will increase by a factor of two. The two-second rule becomes the four-second rule.
To compensate for this, reduce your speed and increase the distance between you and any vehicle in front.
Rain also acts to reduce visibility. Even with your windscreen wipers on, rain can obscure the view through your windscreen. The problem is made worse when windows begin to mist over. To ease such problems:
Dealing With Spray
Water from the sky is not the only problem. Water that is forced up from the road as vehicle drive over it can also cause hazards. This is known as spray. Spray can, in a split second, cover your windscreen and reduce visibility to almost zero.
Heavy vehicles such as trucks and buses cause the most spray, but even a family-sized car travelling at normal speeds can produce enough spray to cause a hazard.
Be extra carefully after a bout of rain has ended, when your wipers are off but when there is still water on the road. If spray hits your windscreen in such circumstances, then you will be effectively blinded until you have switched on your wipers and they have cleared your windscreen.
To keep spray to a minimum, create a good distance between you and any vehicle you are following. If you see a heavy vehicle coming towards you, then switch the wipers to full speed in readiness for a large quantity of water hitting your windscreen.
Aquaplaning
In heavy or persistent rain, as the rain pools on the surface of the road, aquaplaning can become a serious risk. Aquaplaning is when tyres surf the pooled water and lose contact with the road resulting in a loss of traction between tyres and the road. You can tell you are aquaplaning when your steering suddenly appears to become very light.
The way out of an aquaplane is to gently release the accelerator. This slows your car allowing the tyres to regain traction with the road.
When aquaplaning, never brake and avoid trying to steer. If you do, you will be in danger of losing control of your car.
Water on the road is not enough to cause a car to aquaplane. If you are travelling at an appropriate speed, i.e. not too fast, you are unlikely to aquaplane.
Using cruise control on wet roads is not advisable as it can cause problems if you do start to aquaplane.
Roadside Puddles
These can also be hazardous. As a wheel moves through a puddle, drag is caused. This drag can tug at your wheels and cause you to swerve. You will also create spray that may cover your windscreen.
Dealing With Flooding
When confronted by a pool of water blocking your way, whether you drive on through the water depends on how deep it is. If water gets into your engine, the car will stall, and you will cause costly damage. It is recommended that you should never attempt to drive through water that is as high as your car's exhaust pipe. Generally speaking, don't drive through still water that is deeper than six inches or four inches if the water is moving.
If you do drive through a pool of water then: