The Crittenden Automotive Library

How To Aquaplane And Not Crash

How To Aquaplane And Not Crash

Matt Hubbard
Speedmonkey
December 20, 2013

It's mid-winter. It's been raining a lot. It goes dark at 4pm. The puddles are big and the dazzle from other driver's headlights make visibility poor. It's easy to aquaplane.

In short the driving conditions are grim. And it's dead easy to aquaplane right off the road. I've thought about this over the years and adapted my own techniques for dealing with aquaplaning.

Don't be like this idiot and blame the rain. As a driver you know deep puddles are there and you could aquaplane on them, so take control of how you approach driving in these conditions in order to prevent losing control.

First off, we need to analyse exactly what aquaplaning is.

A car has four contact patches - the tyres. A tyre must be in contact with the road surface to generate friction - hence it grips the road. The treads in tyres channel water from the road surface and out behind the tyre, allowing the surface of the tyre to remain in contact with the road.

A given tyre will be able to displace a certain amount of water. If the volume of water on the road is too much for the channels in the tyres to displace then the tyre will temporarily lift above the road surface.

When this occurs that tyre will be aquaplaning and you will not be in control of it. If it happens to more than one tyre you will have lost 50% of grip. If those wheels are the front wheels then the momentum of the car will cause you to continue travelling in the direction you were headed in before you started to aquaplane.

This may well be towards a hedge, barrier, or 44 ton HGV on the other side of the road.

Now we know what aquaplaning is and how it is caused let's look at what you can do about not allowing it to cause you crash.

The car

You may think the car itself has nothing to do with the outcome of aquaplaning. It does. The most important aspect is the condition of the tyres. The legal minimum tread depth of tyres is 1.6mm. This is too shallow in heavy rain. Your tyres should have plenty of tread in order to displace the maximum amount of water. The deeper the tread the more water it will displace.

Also make sure your windscreen wipers are in good order so you can actually see the road, and that your tyre pressures are correct. Too much or too little pressure can affect how the tyres perform both in wet and dry conditions.

Speed

It goes without saying that you have less grip in wet conditions so should drive slower. Specifically when dealing with conditions where aquaplaning may occur - i.e. you have seen a large puddle - you should lower your speed. Remember, the tyre treads can only displace a given amount of water. If you drive faster the tyres have to displace more water so aquaplaning is more likely to occur.

Observation

It goes without saying that large puddles may also be quite deep. The deeper they are the more likely you will aquaplane in them. Also, be careful of puddles at the edge of the road. If wheels on only one side of the car aquaplane you can be pulled into that HGV, so try and avoid them if possible - without swerving about all over the place.

Another crucial aspect is to observe where puddles are in relation to the road. If you aquaplane in a straight line then you should be OK if you act accordingly. If a puddle is anywhere near a corner then different action is needed.

Placement

An aquaplaning car will continue in the direction it was travelling before the loss of control. If you aquaplane on or before a corner your car will continue straight on. Avoid driving through puddles on corners and reduce speed accordingly. If at all possible position your car so that if you do plough straight on you are doing so in such a way as to not leave your lane.

If I see a large puddle on or before a corner I will, if I can and have no other choice, turn ahead of the puddle so the car is facing the direction the road is going in after the puddle. If I aquaplane then it is not off the road but down the road.

Most roads are wide enough to allow a degree of flexibility in positioning without being discourteous to other road users, and without causing a danger to you or anyone else. Use your road position wisely. Imagine that you might travel in the direction you were travelling in for a period after the puddle, and place your car accordingly.

Driving through the aquaplane

You have lost control. Your wheels are travelling above the surface of the road with zero grip. You are moving in a straight line and for a moment have no control over where you are headed.

But in a brief moment your tyres will be in contact with the road. How you drive through the aquaplane dictates what the car does immediately after regaining grip.

It is vitally important to make sure you do nothing suddenly. Do not turn the wheel suddenly, do not accelerate, do not brake. Instead, keep the front wheels in the direction they were in before the aquaplane and stay on the throttle setting you were in beforehand.

In a straight line aquaplane the aim is to come out of the aquaplane with all four wheels pointing forwards and the driven wheels travelling at the same direction as the speed of the car. If you are in a manual car it's worth depressing the clutch in order to allow the wheels to freewheel.

If you brake the wheels will skid when they hit the road surface. This may lead to a loss of control, or someone shunting you up the rear. If you accelerate too much you may spin the wheels more and either aquaplane further or enter wheelspin when you make contact with the road, and crash.

If you over steer you may actually induce a skid when you come out of the aquaplane.

Imagine a rally car jumping over a yump. If his wheels are turned when he hits the road the car will veer out of control, and maybe into a tank slapper. It's the same theory here, and the same goes for braking or accelerating. A rally driver will keep his foot off the brake, and will try and maintain wheel speed with road speed until the point he touches down.

If you have not positioned the car correctly and have aquaplaned on a corner the car will continue to travel in the direction it was already going in - at the angle the car was in before it aquaplaned. In this case you should maintain a steady throttle and do not apply the brakes. Steer gently in the direction you wish to go in after the aquaplane. Do not overcorrect the steering or you will either skid or go into a tank slapper when the wheels regain grip.

After the aquaplane

Presuming you have followed the above advice you will be in a good position to regain control. Everything you do should be smooth and controlled. Don't steer suddenly, or you might skid, don't brake suddenly, or you might skid or be crashed into, don't accelerate suddenly.

Be smooth. Match your wheel's speed with the road speed and your wheel's direction with the road's direction. Once it has happened analyse what you went through and what you did and store it in your memory bank so you know how to react next the time you aquaplane.