How far should you keep from the vehicle in front? Ideally, you should be no closer than the overall stopping distance that corresponds to your speed.

In heavy, slow-moving urban traffic that might not be realistic, as you could be wasting valuable road space. However, even then, the gap should never be less than your thinking distance – and much more if the road is wet and slippery.

A reasonable rule to apply in good, dry conditions is a gap of one metre for each mph of your speed. For example, at 55 mph (88 km/h) a gap of 55 metres would be appropriate. In bad conditions, leave at least double the distance.

A useful technique for judging one metre per mph is to use the ‘two-second rule’.

REMEMBER, your overall stopping distance is the only really safe gap and anything less is taking a risk.

The two-second rule

In good, dry conditions, an alert driver, who’s driving a vehicle with good tyres and brakes, needs to be at least two seconds behind the vehicle in front.

In bad conditions, double the safety gap to four seconds or even more.

How to measure

Choose an obvious stationary point ahead, such as a bridge, a tree or a road sign.

When the vehicle ahead passes the object, say to yourself, ‘Only a fool breaks the two-second rule.’ If you reach the object before you finish saying it, you’re too close to the vehicle in front and need to drop back.

Driving too close to the vehicle in front is a major factor in crashes. You can avoid such incidents by looking well ahead, keeping your distance and giving yourself time to react.

When a vehicle behind is driving too close to you, ease off the accelerator very gradually and increase the gap between you and the vehicle in front. This will give you more time to react if the driver ahead should slow down or stop suddenly.

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