What’s the shortest overall stopping distance on a dry road at 60 mph? Explanation: This distance is the equivalent of 18 car lengths. Try pacing out 73 metres and then look back.

Stopping Distances

What is braking distance?

Formula for calculating the braking distance. The following formula has proven to be useful for calculating the braking distance: (Speed ÷ 10) × (Speed ÷ 10). At a speed of 100 km/h the braking distance is therefore a full 100 metres..

36 metres

Stopping distances on a wet road

Research has shown that at 30mph on a wet road, a car with tyres featuring 8mm of tread can come to a stop in 25.9 metres. Travelling in the same conditions at the same speed, a car with tyres with 3mm of tread will take 35 metres to come to a halt. When the tread is 1.6mm, the stopping distance increases to 43 metres.

A reasonable rule to apply with good dry road conditions is a gap of 1 metre per mph of your speed. Example: 45mph = 45 metre gap.

It is generally accepted that in wet conditions you should double the stopping distance and in snowy or icy conditions the stopping distance should be multiplied by ten. The condition of the road can impact braking distances.

Remember: It takes longer to slow down on icy roads. Increase your following distance to five to six seconds. This increased margin of safety will provide the longer distance needed if you have to stop.

You should:

1. drive at a slow speed in as high a gear as possible; accelerate and brake very gently.
2. drive particularly slowly on bends where loss of control is more likely.
3. check your grip on the road surface when there is snow or ice by choosing a safe place to brake gently.

Ice diggers or ice chisels can be used to break up black ice; ice choppers and ice scrapers for pavement are also options. These tools have thin blades that can penetrate ice or be inserted into a crack between the ice and the pavement to lift and break the ice into chunks. Durable steel shovels may also be used.

Drive in a high gear in snow and ice Driving your car in a higher gear will help you to keep control. If it’s icy and you’re struggling to get started, try pulling away in second gear. This should make it easier to get you going, as pulling away in first gear on ice won’t give you much grip.

While going uphill, use the D1, D2, or D3 gears to maintain higher RPMs and give your vehicle more climbing power and speed. Note: Most automatic vehicles have at least a D1 and D2 gear, while some models also have a D3 gear.

Your car is more likely to skid when the road is icy or covered in snow. In such conditions to avoid skidding you should slow right down. You should also steer and brake very gently. Your stopping distance should also be increased by up to ten times greater than in normal conditions.

If you start to skid, ease off the gas pedal, stop braking, and turn the steering wheel in the direction of the skid. If you can’t control your car on a slippery surface, try to find something to stop you. Try to get a wheel on dry pavement or on the shoulder of the road.

Most skids occur when conditions are slippery. If you find yourself in a skid, take your feet off the pedals. Stop braking and stop accelerating. Then, quickly turn the steering wheel in the direction you want to go.