Chapter 10 – Safety margins

Weather conditions

Driving in Wet or conditions: –

1. Overall stopping distances will be much longer when driving in wet conditions.
2. After driving through flood water the first thing you should do is test your brakes.
3. You should then go slowly while gently applying the brakes, as this will help to dry them. When driving through a Ford (a small stream) remember, it could be more difficult in the winter, use a low gear and driver slowly, test your brakes afterward, there may be a depth gauge, which will show how deep the water is.
4. In wet conditions, your car can aquaplane. This means the tyres have lifted off the surface of the road and are skating on the surface of the water.
5. If your steering suddenly becomes very light, while driving on a wet road, this is a sign that you are aquaplaning. To correct it ease off the accelerator and allow the tyres to regain grip.
6. When driving on a motorway with surface spray use dipped headlights

Hot and windy weather: –

1. In very hot weather the road surface can become soft. This can affect tyre grip and braking.
2. Side winds are most dangerous on an open stretch of road. Side winds are most dangerous for Lorries, Motorcycles, and cyclists. Side winds don’t affect cars.

Driving in icy conditions: –

1. Braking distances on ice and in freezing conditions can be ten times the normal distance
2. When driving on snow or ice use the highest gear possible, as this helps avoid wheel spin. When approaching a sharp bend in such conditions you should slow down and avoid sudden steering movements.
3. If your number plate, windows, lights, or mirrors are covered in snow or ice you must clear them before staring a journey.
4. You can tell you are driving on ice, and black ice, because your tyres make little noise and the steering becomes light.
5. When driving in freezing conditions, avoid sudden steering movements and slow down before you reach the bend.
6. Skidding is usually caused by driver error, driving too fast for the road conditions.
7. To correct a skid, you should drive into it, so if the back of your vehicle slides to the right you should steer to the right

Driving in Fog: –

1. Leave plenty of time for the journey.
2. Only drive when necessary.
3. Reduce your speed, as it is harder to see ahead.
4. Keep well back from vehicles in front, as they may stop suddenly.
5. Turn on rear fog lights when visibility drops below 100 meters (328 feet).
6. Front fog lights should only be used when visibility is seriously reduced. Driving with fog lights on when visibility is above 100 meters is breaking the law.
7. When the fog clears you must turn off fog lights, as they can dazzle other road users and cause brake lights to be less clear.
8. When parking in fog leaves your sidelights on.
9. Before driving in fog check your lights are working and make sure your windows are clean.

Contraflows

A contraflow system is where one or more lanes have a direction of traffic against that of the rest of the carriageway. When you enter a contraflow you should: reduce your speed in good time

1. choose a suitable lane in good time: signs will direct you
2. Keep a safe distance behind the vehicle in front.
3. Follow speed limits.

Anti-Lock Brakes

1. Prevent the wheels from locking which means the tyres are less likely to skid.
2. Allow a vehicle to be steered whilst under braking.
3. May not work as effectively when the road surface is loose or wet.
4. In an emergency apply them rapidly and firmly.
5. They will start to work just as the wheels are about to lock.

Stopping Distances

1. Thinking distance + braking distance = stopping distance.
2. In good, dry conditions leave a 2-second gap between you and the vehicle ahead.
3. In wet weather, leave a 4-second gap.
4. In icy weather, leave a 20-second gap.

The diagram shows the overall stopping distances (thinking distance plus braking distance).

Other Facts to Know

1. Don’t ‘coast’ – travel in neutral or with the clutch pedal pressed down as this will reduce the control you have over the car.
2. When approaching a right-hand bend, you should keep to the left as this will improve your view of the road ahead.
3. When parking facing downhill turn the wheels towards the kerb & put the handbrake firmly on.
4. When parking uphill turns the wheels away from the kerb & put the handbrake firmly on.
5. To control the speed of your car when driving downhill, select a low gear, as this makes use of the engine brake, and use the brakes carefully.