Driving in heavy rain can be hazardous – there's a loss of grip, stopping distances increase and visibility is reduced.
As a general rule, always drop your speed and give yourself more time to slow down. If there’s water standing in puddles on the road surface, your car is at risk of aquaplaning.
What is aquaplaning?
Aquaplaning (also known as hydroplaning) is where a wedge of water forms in front of the tyre and lifts it up off the road surface because the tread can’t displace the amount of water present.
The deeper the water and the faster the vehicle is travelling, the greater the risk of aquaplaning.
Anything the driver does when the car is aquaplaning, such as pressing the brake, turning the steering wheel or accelerating, has no effect on the vehicle.
This loss of traction effectively means your car is out of control, placing yourself, your passengers and other road users at an increased risk of being involved in an accident.
How to deal with aquaplaning
The best ways to recover from aquaplaning are:
- Gently ease off the accelerator
- Take a firm grip of the steering wheel and keep it straight
- Avoid sudden steering movements
- Switch off cruise control, if engaged, and smoothly lift off the throttle
Try to stay calm, and as your car slows down and the tyres regain grip, it should be possible to try the steering and brakes.
Ways to prevent aquaplaning
There are several things you can do to avoid aquaplaning, but broadly speaking they fall in to two categories: tyre maintenance and driving style.
Adequate tread depth is vital for safety in wet conditions as the tread grooves help to remove the water from the contact patch between the tyre and the road surface.
Road safety charity, TyreSafe, claims a tyre with good tread depth can typically clear enough water from the road to fill a bucket in around seven seconds.
As a tyre’s tread depth wears down, its ability to remove water from the road decreases meaning grip levels are reduced and stopping distances are extended.
Current UK law requires at least 1.6mm of tread depth across the central three-quarters of tyres, around their entire circumference.
Drivers failing to comply with these regulations are not only at greater risk of being involved in a car accident, but could also face a fine of up to £2,500 and three penalty points for each illegal tyre.
Checking the condition of your tyre tread depth can be done quickly and easily by taking the 20p test.
To perform the test, simply place a 20p coin into the main tread grooves of your tyre. If the outer band of the 20p coin is hidden when inserted into your tread, then your tyre is above the legal minimum limit.
If the outer band of the 20p coin is visible, your tyre tread depth may be dangerously low and should be checked immediately by a tyre professional.
Insufficient tyre pressure (under-inflation) and over-inflation can also increase the likelihood of aquaplaning because both can alter the size and shape of the contact patch between road and tyres.
Look in your vehicle's manual to find out the correct tyre pressures (front and rear) and check your car's tyre pressures at least once a month.
You can also type your car registration on the Car Pressure Checker page of the TyreSafe website and it will find the correct pressure of your tyres.
If you want to avoid aquaplaning, the most crucial factor is speed and it's especially important to reduce speed when approaching large puddles or areas of standing water.
It's also crucial to drive smoothly. Sudden changes in direction aren’t a good idea at the best of times, but especially in heavy rain. Also, don’t accelerate or brake hard, and read the road ahead so you’re travelling at a safe, steady pace.
Take particular care when approaching bends in the road and allow for a greater stopping distance when approaching junctions – braking distances more than double in wet conditions.
Technology to the rescue
Tyre and technology giant Continental is developing an aquaplaning alert system that uses signals from surround-view cameras and tyre-mounted electronic sensors to warn the vehicle's driver and engage active stabilisation measures.
“Once you feel your vehicle floating, it is too late," said Bernd Hartmann of Continental. "Our aquaplaning assistance concepts detect the early aquaplaning phase to make the driver aware of what is going on under the tyres."