Tyres on public roads are legally required to have a tread pattern. The primary job of the tread pattern is to expel water, which can affect the contact patch with the road in wet conditions, and to provide grip and traction.
When driving on wet roads at high speed, a wedge of water can build up between the tyre and the road surface. The tyre loses road contact, and the vehicle is no longer responsive to steering. This phenomenon is known as aquaplaning or hydroplaning.
Aquaplaning, also known as hydroplaning, is a dangerous driving situation where your tyres lose contact with the road surface due to a layer of water. This typically happens when water builds up faster than your tyres can disperse it, causing your vehicle to “float” and lose traction. Aquaplaning is different from regular skidding because, in this case, the tyres are not touching the road at all – they’re gliding on water.
Aquaplaning is most likely to happen during heavy rain, when puddles form, or on roads with deep ruts and poor drainage. The risk increases with different factors. Understanding these risk factors is key to staying safe:
Driving habits
Driving at higher speeds gives your tyres less time to disperse water, making it easier for a layer of water to build up between the tyre and the road. Sudden braking and accelerating on wet roads can trigger aquaplaning.
Tyre condition
Incorrect tyre pressure (underinflation) and wide, low-profile tyres can increase the risk. Also, worn tyres with shallow tread (near the 1.6 mm legal limit) are far less effective at clearing water.
Vehicle weight
Lighter vehicles may aquaplane more easily, as they exert less pressure on the tyres. However, heavier vehicles are not immune – worn tyres or deep water can still cause loss of traction.
Pavement type
Smooth or worn road surfaces are more prone to water buildup, while rougher surfaces may help channel the water away.
Recognising aquaplaning quickly is crucial for your safety. Look out for these warning signs:
If you notice any of these symptoms, act immediately to regain control and avoid potential accidents.
Taking proactive steps can greatly reduce your risk of aquaplaning. Follow these best practices:
New tyres are capable of dispersing up to 30 litres of water a second at 50 mph). But the depth of the tyre tread wears down over the course of regular usage. Consequently, tyres disperse significantly less water as the depth of the tyre tread decreases.
If car tyres only have a tread depth of 1.6 mm, for example, then water displacement is effectively and dramatically reduced. With a remaining tread depth of 3 mm, tyres can still retain a high amount of their water displacement capability.
After this point, the risk of hydroplaning increases dramatically. In addition, a diminished tread also affects braking performance. The more worn the tread on a car’s tyres becomes, the longer it takes to come to a complete stop, as test results show.
In a test performed at Continental’s test location Contidrom, the braking distance increased by 6.8 metres on tyres with the legal minimum tread depth of 1.6 mm, compared to the full thread depth of 8 mm. Tyres with a 3 mm tread only took 2.2 metres longer to come to a full stop.
If you find yourself aquaplaning, follow these steps to stay safe:
Whether your tyres are new or old, drivers should always slow down on wet road surfaces to reduce the risk of aquaplaning.
If aquaplaning should occur – which is still possible depending on weather and road conditions that a driver cannot prevent – drivers are advised to immediately take their foot off the gas pedal and depress the clutch. Avoid moving the steering wheel or braking suddenly.
However, if there is a danger of a collision or severe accident, the emergency brake should be initiated at once. In most cases, the rear wheels will still have enough grip to slow the vehicle.
As soon as the tyres are back in contact with the road and traction is regained, it should be safe to continue driving at reduced speed.
