What is aquaplaning?

Wet and wild – aquaplaning and how to avoid it

If you're familiar with life in the UK, you won't be shocked to hear that it rains here. A lot. Though this is annoying for many reasons – like having to run outside to bring in the washing, for one – it can increase the risk of an accident on the roads.

Even if it sounds like something James Bond would get up to, it's important to know what aquaplaning is. Here's what causes it and how you can best avoid it to stay safe on wet roads.

Car aquaplaning in puddle of water

What is aquaplaning?

Aquaplaning – sometimes known as hydroplaning – is when water builds up in front of your tyres faster than the weight of your car can displace it. This forces water below the tyre, creating a layer of water between your tyre and the road.

Because of this, your tyres lose their grip on the road. With no traction, you could lose control of the car temporarily, and be unable to steer, brake or accelerate. You might notice the engine suddenly getting louder or the steering suddenly going 'light'.

What causes a car to aquaplane?

For a car to aquaplane there needs to be standing water on the roads. Once there's standing water, the risk of aquaplaning is affected by three factors:

  • Speed – it's always important to lower your speed when it's raining heavily, especially if it's enough to form puddles or standing water. Aquaplaning is most likely to occur at higher speeds, and sudden accelerations could cause your car to aquaplane.
  • Tyre tread – worn tyres with low tread depth won't clear water from the road as effectively as newer tyres, upping your chances of aquaplaning.
  • Water levels – the deeper the water is, the harder it’ll be for your tyres to keep a steady grip. Standing water and puddles can often be deeper than you might think, so always drive with caution.

How to avoid aquaplaning

  • Plan your journey ahead of time. Keep your eye on warnings for severe weather conditions
  • Keep your driving smooth and steady - avoid harsh braking and hard cornering.
  • Regularly check your tyres, making sure that they're inflated to the correct pressure.
  • Consider changing tyres before they reach the legal minimum tyre tread of 1.6mm, especially if you're driving in winter when roads are more likely to be wet.
  • Puddles tend to form at the side of the road, along the pavement. If it’s been raining or there's standing water across the road then it'll often be shallower towards the centre-line. 
  • Avoid driving in any ruts in the road caused by heavy goods vehicles. These can be full of water even if the rain has stopped.

What to do if you aquaplane

If your vehicle begins to aquaplane you should:

  • Avoid slamming the brakes. It might be your first instinct to stop the car, but you could end up causing your car to lose control and spin.
  • Slowly and gently ease off the accelerator, making sure you hold the steering wheel straight and steady.
  • When you feel yourself gaining more control of the car, brake to bring your speed down.

Remember to also consider your stopping distances. Even without standing water and no risk of aquaplaning, stopping distances in wet weather will always be much longer, simply because your tyres have less grip. Keep at least twice the stopping distance you would in dry conditions.

Published: 4 June 2019 | Updated: 18 December 2020 | Author: The AA

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