Engines are least efficient when they're cold; they take a few minutes to reach their operating temperature. Similarly, the catalytic converter needs to heat up before it operates efficiently. So, on short journeys, the vehicle will use more fuel and release more harmful exhaust gases into the environment. It may be quicker - and better for your health - to walk or use a bicycle.

If you brake while travelling in a straight line, the inertia of the vehicle tries to keep it moving forward. This moves the weight of the vehicle forward and onto the front wheels. This extra load on the front tyres will press them more firmly into contact with the road, giving more tyre grip.

You can't deal safely with a hazard by looking solely ahead. You'll also need to consider how your actions will affect any drivers behind. As soon as you recognise a hazard, use the mirrors to assess how other road users will affect your planning.

There's usually a 30 mph speed limit where street lights are less than 185 metres (600 feet) apart.

raffic-calming measures, such as road humps, chicanes and narrowings, are intended to slow traffic down and to protect vulnerable road users. Maintain a reduced speed until you reach the end of the traffic-calming zone.

This sign indicates a route for trams only. Other vehicles aren't allowed to use these routes. Drivers need to look ahead and plan - especially in an unfamiliar area.

When an emergency vehicle is behind with its blue lights flashing, you must remain calm and look ahead for a safe place to move over to let it pass. If you're waiting at red traffic lights, don't attempt to clear the way by driving past the red light; this is both dangerous and a traffic offence.

When parking a vehicle with automatic transmission, the gear selector should be moved to the 'P' (Park) position. This locks the transmission and prevents the vehicle from moving forwards or backwards. This will stop it from rolling away should the parking brake fail.

You normally join a motorway from a slip road on the left. Join where there's a suitable gap in the traffic travelling in the left-hand lane. You should adjust your speed to fit in with the traffic flow in the left-hand lane, but you must give way to the traffic already on the motorway. Don't try to force your way into the traffic stream.

Loose gravel or chippings can easily be thrown up by vehicles' tyres. At roadworks or on newly surfaced roads, check your speed and keep a good distance away from vehicles ahead to avoid any flying chippings.

If your pupil's driving is below the required test standard, it's your responsibility as a professional instructor to advise them not to take the test. As soon as you become aware of a possible problem, you should discuss this with your pupil and positively encourage them that, in their interest, and for other road users as well, it would be far better to postpone the appointment. If you can't dissuade them, then you should withhold the use of your vehicle. Ultimately, it's the pupil's test and an instructor can't prevent them from taking it in someone else's vehicle.

When approaching a contraflow system, slow down in good time and obey reduced speed limits. You may be travelling in a narrower lane than normal, with no permanent barrier between you and the oncoming traffic. Be aware that the hard shoulder may be used for traffic, and the road ahead could be obstructed by slow-moving or broken-down vehicles.

Large, long vehicles need extra room when making turns at junctions. They may move out to the right in order to make a left turn. Keep well back and don't attempt to pass on the left.

At a pelican crossing, the green light means you may proceed as long as the crossing is clear. If someone hasn't finished crossing, be patient and wait for them.

If a motorcyclist has been injured, it's important not to remove their helmet unless it's absolutely essential to keep them alive.

The differential mechanism enables the inside wheel to turn at a slower rate than the outer wheel when the car is being driven on a curve. This helps both stability and grip while the car is cornering or turning.

As you approach traffic lights that have been on green for some time, anticipate that they'll soon change. Check your mirror so that you know what traffic is behind you and how far away it is. If the lights change to steady amber, you should stop behind the stop line. If you're so close to the stop line when the lights change that to stop may cause a collision, you should continue. You'll only know the risk from traffic behind if you use your mirrors as you approach the lights.

To go straight ahead at a roundabout, you should approach it in the appropriate lane. Where there are road markings, use the lane indicated. To help traffic on the roundabout and traffic waiting to join, you should give a left signal just after you pass the exit before the one you want. If you have to change lanes to reach your exit, do so with care and consideration.

The colours of the reflective studs on the motorway, and their locations, are
- red - between the hard shoulder and the carriageway
- white - between the lanes
- amber - between the edge of the
carriageway and the central reservation
- green - along slip-road exits and entrances bright green/yellow - at roadworks and contraflow systems.

Using a hand-held mobile phone while you're driving is illegal. Driving requires all of your attention, all of the time. Any distraction, however brief, is potentially dangerous and could affect your control of the vehicle. Even using a hands-free system will distract you. The only safe way is to switch your phone off and make or pick up calls when you stop for a rest break.

It's especially dangerous to park on the road in fog. If it's unavoidable, then leave your parking lights switched on.

Give way to traffic already on the motorway. If you've matched the speed of traffic in the left-hand lane, you should be able to join where there's a suitable gap in the traffic. Try to avoid stopping at the end of the slip road - but you might have to do so if the motorway is very busy and there isn't a safe gap in the traffi

You must obey signals given by police officers, traffic officers, traffic wardens and signs used by school crossing patrols. When a police officer signals to you to stop, you should stop safely on the left and switch off your engine.

During periods when ATM is in operation, the hard shoulder is used as an extra driving lane. When ATM isn't in operation, the hard shoulder resumes its normal role as a refuge for breakdowns or emergencies.

If someone's been injured, the sooner proper medical attention is given, the better. Either ask someone to phone for help or do so yourself. Only move an injured person if there's a risk of further danger. Don't remove an injured motorcyclist's helmet unless it's essential.

In some situations, you may feel that your indicators can't be seen by other road users. If you think you need to make your intention more clearly seen, give the appropriate arm signal.

The flashing amber light comes on after the red light, and people may still be crossing. If the crossing is clear and it's safe, you may drive on without waiting for the green light.

When a candidate passes a practical driving test, their full licence is normally issued directly by the licensing authority. However, if this doesn't happen, successful candidates should apply for a full licence as soon as possible. The driving-test pass certificate is valid for two years; if a full licence isn't applied for within that time, the driver will need to retake their test.

The purpose of this road marking is to keep the junction clear of queuing traffic. You may only wait in the marked area when you're turning right and your exit lane is clear but you can't complete the turn because of oncoming traffic.

When preparing to turn left into a side road, you should be prepared for obstructions or vehicles that may wish to stop and park. This could be before or after the turning.