PCV Free Theory Test

If diesel fuel becomes very cold, it can partially solidify. Additives are used by the fuel companies to try to prevent this. Any solidifying (waxing) of the fuel can prevent it from flowing properly and cause the engine to run erratically or even stop.

Tyres can become very hot during sustained high-speed driving. If they're under-inflated or damaged, there's a risk they'll burst or disintegrate. Check for excessive heat when you stop for a break.

Warning buzzers are linked to many systems on modern vehicles, including the air brakes. A warning light on the dashboard may help you identify the system that's caused the problem. Stop in a safe place until the fault has been identified and put right. Get professional help if necessary.

If you're carrying a load that consists of loose materials, it must be covered by suitable sheeting. You mustn't risk losing any part of your load. This could cause damage or injury to other road users, and you would be responsible.

Under no circumstances should you attempt to move or drive a vehicle with an air leak in the braking system. Report the fault immediately, or arrange to have it repaired. Place a warning sign in the cab, telling other drivers not to drive the vehicle and why.

When you're being overtaken, the other driver has to decide when it's safe to complete the manoeuvre. Don't give an unofficial signal, however well intended. There may be a hazard you're unable to see from your position.

This sign is placed on sections of road where overtaking would be dangerous. There'll often be a plate underneath the sign, telling you how far the restriction extends. You mustn't overtake until you pass another sign cancelling the restriction.

Keeping your vehicle's tyres in good condition will give them a good grip on the road and will improve the vehicle's overall stability. Each tyre must have at least the minimum legal depth of tread across three-quarters of its width. Renew tyres well before they wear to less than that.

A toucan crossing is signal-controlled, but unlike a pelican crossing it doesn't have a flashing amber light in the sequence. Cyclists and pedestrians cross together, and cyclists are allowed to ride their bicycles over the crossing.

If you see this sign, be aware that there's a danger of grounding. This can happen where there's a pronounced bump in the road, such as at a level crossing or a hump bridge.

You must always disengage the diff-lock as soon as the vehicle is moving. The differential allows the rear wheels to revolve at different speeds, and this allows the vehicle to follow a curved path. Attempting to turn with the diff-lock engaged could result in the vehicle continuing straight on.

Solid white lines are used where it would be dangerous to overtake. If the solid line is on your side of the road, you may cross it to pass a stationary vehicle, or to overtake a pedal cycle, horse or road-maintenance vehicle that's travelling at 10 mph or less. You may also cross the solid line to enter premises or a side road.

When an ambulance is displaying a flashing blue light, try to stop in a safe place to allow it to pass. Make sure you don't endanger any other road users or commit an offence; for example, by driving past a red traffic light.

A heavy vehicle will lose speed when climbing a steep hill. Changing to a lower gear will help you to maintain an appropriate speed.

If you're disqualified from driving because you were two-and-a-half times over the legal limit, you'll be classified as a high-risk offender. Before you can regain your licence, you'll have to satisfy the Driver and Vehicle Licensing Agency (DVLA) that you don't have an alcohol problem.

Pedestrians and cyclists are shown the green light together. The signals are push-button-operated and there's no flashing amber phase.

Don't hurry elderly people across the road by getting too close to them or revving the engine. Be aware that they might take longer to cross. They might also have hearing difficulties and not hear you approaching.

When discharging a load from a tipper vehicle, the centre of gravity is raised as the tipper body rises. To avoid the vehicle rolling over, it's vital that it's positioned on a level, solid surface before the tipper mechanism is engaged.

Look for and obey traffic signs. Disobeying or not seeing a sign could be dangerous. It may also be an offence for which you could be prosecuted.