Often you will hear racing drivers talking about oversteer and understeer, but what exactly are they talking about? Does it commonly occur, or is it just limited to motorsports and young lads showing off? Here is a rough explanation of what each term means.

Understeer

Imagine you're driving a car, and turn the car into a bend. However, the vehicle doesn't respond and keeps going straight, or it turns in but not as much as you would like.

This is understeer. Basically, the front wheels slip on the road surface, allowing the car's momentum to push it straight on. When understeer occurs, the steering will feel lighter and somehow not connected to the front wheels. Most modern cars are set up to understeer before anything more serious will happen.

There are two ways of dealing with this.

• The first is to keep the throttle steady and wind more steering lock on. This has the advantage of keeping the car stable in attitude throughout.

• The second, much harder option, is to ease off the throttle and keep the steering lock where it is. On front wheel drive cars, this allows the wheels time to grip the road and turn, although a gentle easing off is required to keep the car stable (see 'lift-off oversteer' below).

Oversteer

Imagine you're driving a car and turning into a bend. However, you only put in a small steering input and the car turns in much more sharply than you anticipated.

This is oversteer. The rear wheels are going faster than the fronts, pushing the vehicle around. Sometimes the rear wheels will slip more than the front when cornering on slippery roads, leading to the same effect as vehicle momentum and weight distribution can push the rear of the car around.

The best way to counter this is with an armful of opposite lock while keeping the throttle steady; ie, turn the steering wheel in the opposite direction. This should counteract the oversteering effect, although it takes skill to tell how much opposite lock is needed.

This is also tutored by driving schools as turning into the skid: in other words, if the rear of the car is coming round to your right when going around a left hand bend, turn the steering wheel to the right.

If you have a choice, never, ever, sharply lift off the throttle when oversteer occurs. This will seriously upset the balance of the car and may make the situation worse.

A Subset - Lift-Off Oversteer

Sudden changes in throttle mid-bend, on any type of vehicle, are usually the best way to see how fast you can embed yourself into a hedge. This phenomenon is called 'lift-off oversteer'.

At the point of throttle lift-off, there is usually a larger amount of steering lock than strictly necessary applied at this point. When the throttle is released, the car suddenly follows it and the sharp change in throttle settings upsets the vehicle. This causes the vehicle to corner more sharply than intended or, in extreme cases, causes it to lose grip completely¹.

A Slightly Different Case - The Four-wheel Drift

This happens when all four wheels have very little grip on the road, and the vehicle slides in whichever direction it wants to. It is often manifested as an extreme case of understeer, where the whole vehicle is slipping, not just the front wheels.

The generally recommended course of action is to turn gently into the direction of the skid, so that the vehicle has a chance of steering itself out of it.

Alternatively, if you have a clear road, are confident of yours and the car's abilities, and are having fun, it is possible to hold the slide by careful balance of the throttle and steering. Powerful rear and four-wheel-drive cars can be provoked into power slides, which is effectively a steering and throttle controlled four-wheel drift; see any Jeremy Clarkson or rallying video for evidence. However, it must be stressed that this isn't a tactic to be used as a matter of course on public roads!

As before, avoid stepping on the brakes or lifting off the throttle, as this will only make the skid worse.

A good pictorial explanation of oversteer and understeer from a Formula One driver's perspective can be found at The Car Behaviour Guide.

How to Avoid Over- and Understeer

All advice can be summarised as follows:

• Tyres - Make sure all your tyres have good tread and are at the correct pressures. Also, be wary if intending to drive hard on so-called 'fuel saver' tyres. These are often low friction to help fuel economy, and this means less grip is available.

• Roads - Be aware of camber changes and uneven road surfaces as these can all upset your vehicle. Some types of surface offer different grip levels, so be aware of that.

• Weather - Wet or damp weather is tricky, as it will often make roads extremely slippery. If the road surface looks very shiny, it's very waterlogged, so drive with caution.

• Speed - Above all, drive at appropriate speeds and leave sensible distances between yourself and other vehicles. That way, if trouble does happen, you have time to react and room to get out of it. Don't assume that because you can't see something, it isn't going to happen.

• Stability - Keep the vehicle as stable as possible. Avoid sudden, sharp changes to the throttle, brakes or steering, as this will unsettle the car. The most stable vehicle is one under gentle acceleration. If at all possible, aim to get all your gear changing and braking done before you enter the bend, so you can accelerate out.

Never assume that because a road was fine yesterday and the day before, it'll be fine today ².

For more advanced driving techniques, there are some good ones in the h2g2 entry surprisingly entitled Advanced Driving Techniques. There is also quite a bit of useful information on driving in general at BBC Motoring.

That said, good judgement comes with experience - and a lot of that comes from bad judgement!