ALT-1 Driver Safety how to Drive through a Hydroplane
Hydroplaning, also known as aquaplaning is a phenomenon of wet weather driving. The rather frightening consequence for the driver is that it removes directional control of the car from them. This article will look at the causes of hydroplaning, its effects, and how to remedy the situation.
Road tires are treaded and, in wet weather, the grooves in the tires are critical to maintaining contact between the tire and the road surface. The grooves are designed to dissipate water but occasionally, in extreme conditions, they cannot move enough water from underneath the tire. In this scenario there is effectively a barrier of water between the tire and the road. The car is now hydroplaning.
There are various reasons why there may be too much water for the tires to shift. Driving too quickly on a wet road can result in water hitting the tire faster than the grooves can get rid of it. Another danger is deep standing water, when the tire is suddenly confronted by a much larger volume of water than it has previously been dealing with. Rivulets of water running across a road can also pose a hazard.
Once a car has started to hydroplane the driver could be forgiven for thinking that they are merely a passenger, but this is not the case. Steps can be taken to regain control of the vehicle. The principle point to remember is that no sudden inputs should be made to any of the car's controls. Although the driver has no directional control over the car while it is hydroplaning any steering adjustments should be small and gently made. The reason for this is that, when the car eventually does regain grip with the road surface, it is preferable to have the vehicle pointing as straight as possible. Otherwise, oversteer can occur resulting in a slide or spin. Oversteer is when the rear wheels of a car break traction and tends to happen more in rear-wheel drive cars. The opposite effect to this is understeer, when the front wheels are reluctant to turn into a corner.
During hydroplaning the most useful tool for the driver in regards to remedying the situation is the accelerator pedal. By gently reducing pressure on it the speed of the car will also decrease. Less speed means that the tires will have less water to deal with and the car will eventually regain contact with the road. Sudden braking is strongly advised against as this can result in the vehicle regaining traction very abruptly. Like sudden steering inputs this can result in the car behaving erratically. Fishtailing, sliding and spinning are all possible consequences, not to mention the danger of being struck by a vehicle following behind.
Technically, hydroplaning can also refer to hitting ice as it is just frozen water. It is important to note that the technique for regaining control of a car on water is slightly different to that required for ice. While it is advisable to slowly let off the accelerator pedal the brake pedal should not be touched at all. Any braking input can severely destabilize a car on ice and cause it to veer suddenly or even spin. Unlike hydroplaning on water, the driver has no influence on when the car will regain traction on ice. This will only happen when the car has left the ice patch. In particular wintry climates it is a very good idea to invest in a set of studded tires. The studs dig into the ice giving much better road holding.
Ideally for drivers they will not have to deal with hydroplaning as they will not encounter it in the first place. In this respect there are several ways of lessening the likelihood of it happening. As has been mentioned throughout, tires are critical. Regular checks should be carried out to measure tread depths and, if they are borderline legal, have the tires changed. The Royal Society for the Prevention of Accidents (RoSPA) recommends that tires should be changed once tread depth has reached 3mm. Below this depth tests have shown that braking performance in the wet deteriorates dramatically.
Adjusting driving speed to suit the conditions is also a way of minimizing the risks of hydroplaning. Cars do not perform as efficiently in the wet as they do on a dry road, so extra care must be taken. Braking distances are lengthened and cornering speeds decrease. Any changes in speed or direction should be made smoothly and thought out in advance.
Keeping a safe distance from vehicles in front is essential. What is considered a safe distance in the dry must be increased considerably on a wet road. If anything happens in front of you increased braking distances mean that more space is required to take avoiding action.
Rain also causes reduced visibility so having the car's lights turned on is essential. When passing cyclists give them a wide berth as they may not see you or may be swerving to negotiate around puddles themselves.
When approaching standing water on a road try and ensure that the car's wheels are pointing straight. A car which is already turning when it begins hydroplaning will be considerably harder to regain control of.
If possible follow the same line as vehicles in front of you. If they are only a short distance in front their tires will have already displaced the water giving your tires less to deal with.
Take great care when approaching junctions. In wet weather it can be hard for other people to see you and they may pull out without warning, requiring you to perform an emergency stop.
If you find your car hydroplaning have a quick look in your rear-view mirror to see the distance to any vehicles behind you. If there is a vehicle close behind reduce your speed very slowly until your wheels regain contact with the road. Remember that drivers behind will also require greater time and distance to respond to anything you do.
It should be remembered that hydroplaning can affect any driver, irrespective of their ability or experience. Even for very skilled drivers it can be a daunting experience. It is perhaps comforting to know that even the best drivers in the world can find it to be a frightening situation, although they are travelling at far greater speed. Triple Formula 1 World Champion Sir Jackie Stewart provided an insight into his experiences of hydroplaning during a particularly wet race:
in fog and ceaseless spray you just have no idea at all. In addition you are continually worried by the fact that you are aquaplaning and almost always losing control, and you feel sure that the man in front is doing the same thing so that at any moment he is going to appear just in front of you pointing in the wrong direction With only 3 laps to go it really started to pour down with rain all round the circuit, and the track became really treacherous I entered an S' bend in third gear and suddenly lost control in a deep river of water which was running across the road. The car immediately started sliding I was hurtling across the road towards a marshal who was standing beside his post completely unprotected I knew I was going to hit him. But just then the wheels got a little bit of grip and I managed to regain control.'
The main thing to remember when a car hydroplanes is to remain relaxed and be confident that you can retrieve the situation without great drama. The problems really start when a driver panics and makes erratic inputs to the car's controls. Better still, slow down, keep your car well maintained, and you may well never experience it.
Sources:
My Greatest Race' (Jackie Stewart)Principles of Performance Driving' (Jackie Stewart)Principles of Race Driving' (Ayrton Senna)Royal Society for the Prevention of AccidentsWikipedia
