Skids and aquaplaning

By the end of this topic you can

• You can explain the main causes of skids.
• You can drive smoothly to reduce the risk of skidding.
• You can describe how to correct a skid.
• You can brake correctly in an emergency in a car with ABS.
• You can recognise and respond to aquaplaning.

What you need to know and understand

• Skidding is usually caused by the driver braking, accelerating or steering too harshly, or driving too fast for the conditions (Highway Code rule 119).
• If you skid, remove the cause by releasing the brake pedal fully or easing off the accelerator, and steer in the direction of the skid (rule 119).
• If the rear of the car skids to the right, steer to the right to recover (rule 119).
• With ABS, in an emergency press the brake firmly and keep the pressure on until you have slowed enough. ABS helps you keep steering control but does not always shorten stopping distances (rule 120).
• Light or unresponsive steering in the wet usually means water is stopping the tyres gripping. Ease off the accelerator and slow down gradually (rule 227).
• After driving through deep water, test your brakes gently, as they may be less effective (rule 121).
• Car tyres MUST have at least 1.6 mm of tread across the central three-quarters of the tread, all the way round (Highway Code annex 6).

Why cars skid

Your tyres can only provide a certain amount of grip. Braking, steering and accelerating all use some of it. Ask for too much at once, for example by braking hard while turning, or reduce the grip with water, ice, mud, leaves or diesel, and the tyres slide.

Worn tyres, wrong tyre pressures and travelling too fast make skids far more likely. Coasting with the clutch down or in neutral also reduces control, especially downhill (rule 122).

If the car starts to skid

Stay calm. Sudden, jerky reactions make a skid worse.

1. Take your foot off whatever caused the skid: release the brake fully, or ease off the accelerator.
2. Look where you want the car to go.
3. Steer smoothly in the direction of the skid. If the back slides to the right, steer right.
4. As grip returns, straighten the wheel gently so you do not skid the other way.
5. Once back in control, slow down and drive more gently for the conditions.

Emergency braking and ABS

Most modern cars have ABS, an anti-lock braking system. It stops the wheels locking when you brake hard, so you can still steer. In an emergency, brake firmly and keep the pressure on. You may feel the pedal pulse or hear a noise; this is normal. Do not pump the brake.

ABS does not create grip. On a slippery road you will still need much more distance to stop, so leave bigger gaps. Without ABS, try not to brake so hard that the wheels lock (rule 118).

Aquaplaning and standing water

Aquaplaning usually happens at higher speeds on standing water or heavy surface water. The steering suddenly feels light and the engine may rev as the wheels lose grip. Ease off the accelerator, hold the wheel steady and let the car slow gradually. Do not brake hard or steer sharply.

Prevention is better: slow down in heavy rain, avoid large puddles when it is safe to do so, and keep your tyres in good condition. After you drive through deep water, test your brakes gently.

Common mistakes

• Braking hard while steering on a slippery bend. Brake on the straight before the bend.
• Pumping the brake in a car with ABS. Press firmly and keep pressing.
• Steering sharply when the steering goes light. Ease off and hold steady.
• Ignoring worn tyres. Check tread depth and pressures regularly.

Test yourself: Skids and aquaplaning

Answer each question, then read the explanation. Questions come in a random order each time.

Go deeper

• Skids, Aquaplaning and ABS