Block' gear changing means changing up or down to the most appropriate gear without going through each gear in turn. It reduces the number of gear changes, and this can improve fuel consumption.

Following the vehicle manufacturer's guidelines for service intervals will enable worn components to be replaced before they fail. This will help prevent costly breakdowns.

If the air-pressure warning activates, you should have enough air to allow you to stop safely on the hard shoulder. Don't delay stopping, as further loss of air may cause the brakes to lock on. Switch on the hazard warning lights. Use the nearest emergency telephone to call for assistance.

Always get expert advice when dealing with tyres. It's good practice to have a new valve fitted when replacing a tubeless tyre. Good garages and specialist tyre services know the regulations.

A warning-lights check is sometimes performed automatically when the ignition is switched on. However, you may need to do this manually by operating a separate check switch. Never start a journey without carrying out this check. If there's a problem, have it repaired before you set off.

Before leaving the cab, it's very important to secure the vehicle by applying the parking brake. After leaving the cab, apply the trailer parking brake.

The handling of a six-wheeled bus or coach is not much different from that of a two-axle vehicle, except that punctures can be more difficult to detect.

Most diesel engines have glow plugs to preheat the combustion chambers, so helping the engine to start when it's cold. When the ignition is switched on, the preheat warning lamp will show and the glow-plugs will rapidly heat up. In cold weather, the starter should only be operated when the glow plugs reach operating temperature and the warning light goes out.

Today, all water-cooled engines use a mixture of water and anti-freeze to make up the coolant. As well as helping to keep the engine at its correct operating temperature, the anti-freeze acts as a corrosion inhibitor to prolong the life of the cooling system.

It's a legal requirement that your tyres have at least the minimum permitted depth of tread and are in good condition before you start any journey. Make sure that you inspect them before setting off, and at regular intervals.

Depending on road speed, pressing the accelerator pedal firmly to the floor will activate a switch that allows the gearbox to select a lower gear for improved acceleration.

If the steering becomes heavy, the power-assisted steering may have failed. It's also possible that your vehicle has a puncture or the load might have shifted. You should stop safely, investigate the cause and call for help if necessary.

To comply with the law, all lights must be in good working order, even in daylight when they're not being used. Before you set out, make sure that everything is working and get any faulty lights fixed. You may need to use your headlights or other lights if you're delayed or find yourself driving in conditions of reduced visibility.

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.

As the lubricating oil is pumped around the engine, it collects tiny fragments of metal from the moving parts. The oil filter is designed to remove these fragments. Most filters are designed to be replaced at service intervals.

If you overfill the engine with oil, you could cause the engine to build up too much pressure when it's running. This could cause damage to oil seals and gaskets.

Your tyres must be in good condition and properly inflated to the manufacturer's recommended pressure. Research has shown that the tyres most likely to fail are those that have been over-inflated.

Lack of oil could cause the engine to seize, and this could cause sudden and unexpected loss of control. You could break down in a dangerous position and put yourself and other road users at risk.

Driving at higher speeds and for longer periods, such as on motorways, can cause your tyres to overheat and disintegrate. You should make a point of checking them when you stop for a break.

Continuous high speeds on the motorway can cause the tyres to become hot and to shred. If you notice this happening, you must stop on the hard shoulder as soon as it's safe to do so. It's dangerous to drive a defective vehicle.

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.

Faulty power steering will make your steering wheel very difficult or almost impossible to turn. Continuing to drive could cause danger to you and other road users. You should park safely and get help.

Always make sure your vehicle is secure and level before a wheel is changed. Apply the parking brake and use chocks if they're available. When the replacement wheel is fitted, all wheel nuts/studs should be retightened to the correct torque. On a motorway, never attempt to change a wheel yourself. Use the emergency telephones to call for assistance.

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.

All tyres must be properly inflated and in good condition. Tyre failure on a motorway can have serious consequences. This can be avoided by checking your tyres at the start of each journey.

When a tyre explodes, fragments are thrown over a wide area. This can create a serious hazard for other drivers. You should regularly check your tyres for cuts, damage and pressure. Frequent checks and proper maintenance can help prevent a blow-out.

DVSA and the police carry out frequent roadside checks of commercial vehicles. Where serious defects are found, the vehicle is taken out of use until they're put right. Details of the prohibition are shared with the traffic commissioner.

Workshop manuals give detailed technical advice about the servicing, maintenance and repair of your vehicle. They're essential for anyone who wants to service or repair their own vehicle.

If the engine contains too much oil, the moving parts can hit the oil surface, causing a loss of power or even damage to the engine. Excess pressure may damage oil seals, causing oil to leak onto the road, creating a slippery and dangerous road surface.

The ignition light should go out when the engine has started. If it fails to go out or comes on while you're driving, it means that there's an electrical fault of some kind.

Codes are shown on the wall of the tyre. These refer to the maximum load and speed capability of the tyre.

Coolant solution is also known as anti-freeze. It provides protection from freezing and also contains a corrosion inhibitor that prolongs the life of the cooling system. Remember to check the coolant level regularly.

You should check your oil level regularly and pay attention to any oil warning devices. A damaged engine can be very expensive to mend. It could also cause sudden and unexpected loss of control, putting you and others in danger. If your engine seizes, you should make every effort to stop in a safe place.

Heavy steering could mean there's a fault with the power steering. It should be investigated as soon as possible. Many large vehicles can become undriveable if the power steering fails completely.

Maintenance of the fifth wheel should be carried out regularly, ideally monthly or every 10 000 km.

Too much oil in an engine can be just as bad as too little. Overfilling an engine can create excess pressure, cause oil leakage through seals and result in expensive damage.

Modern large vehicles are fitted with power-assisted steering. If the steering feels heavy, then there's likely to be a fault, which should be investigated and repaired as soon as possible.

On multi-axled vehicles, the inside wheels on the rear twin-axle are the most difficult to check for punctures and damage. A deflated tyre will transfer the weight to the second tyre of the twin-axle pair. This will overload it and could cause it to burst.

In extremely cold weather, you'll have to use diesel fuel with anti-waxing additives to stop the fuel lines from freezing up. During the winter months, these additives are usually put in by the fuel companies.

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.

Just like your bus tyres, your trailer tyres must be in good condition. You might not tow a trailer on every journey you make, but when you do, check the trailer tyres while they're cold and make sure they're suitable for the load they'll carry.

In cold weather, diesel fuel can solidify as it starts to freeze. This is known as waxing. Waxing prevents the fuel from flowing properly and this can stop the engine from running.

Most diesel engines use a high-pressure fuel-injector system that will deliver pressurised fuel directly into the combustion chamber of the engine. This system is known as a direct-injection engine.

You have a legal responsibility to make sure that your vehicle is fully roadworthy. Daily walk-round checks give you the chance to look for any defects with your vehicle.

When changing or fitting new tyres, consider buying energy-saving tyres. These have a reduced rolling resistance and improved efficiency, which helps to keep fuel costs down.

The vehicle handbook will clearly explain what maintenance may be carried out by the driver. Always refer to it and comply with the safety guidance that it contains. However, you need to be aware of your employer's policy on making any minor repairs.

All tyres must be properly inflated and in good condition. Tyre failure on a motorway can have serious consequences. This can be avoided by checking your tyres at the start of each journey.

You should be familiar with all warning lights and buzzers fitted to your vehicle. If you're driving the vehicle for the first time, make sure that you know the function of each. If the brake warning light shows a fault in the system, stop as soon as it's safe to do so. Report the fault, and don't continue until it's been corrected.

If you overfill the engine with oil, you could cause the engine to build up too much pressure when it's running. This could cause damage to oil seals and gaskets.

Oil is vital for lubrication of the engine. It should be checked regularly and topped up as necessary. You should always check your engine's oil level when the engine is cold and your vehicle is parked on the level.

If you notice any missing wheel nuts, park and phone for assistance. It's essential that all wheel fixings are in place and tightened to the torque specified by the manufacturer. Checks should be made before you start any journey, but make a visual check every time you start up again after a rest stop.

Always have a walk round your vehicle and visually check the wheel nuts whenever you take a break. When a wheel is replaced, it's important to have the wheel nuts rechecked shortly after their initial tightening. Wheel nuts must always be tightened to the torque specified by the manufacturer.

Many buses and coaches have a large panel of warning lights on the dashboard. A system check built into the ignition system will allow you to check that all the warning-light bulbs are working before you start your journey. If a warning light stays on, there's a fault. Have it checked before continuing. Remember, your passengers' lives are in your hands.

When a wheel is refitted, the wheel nuts/studs should be tightened gradually and diagonally across the wheel. You should tighten the nuts to the specified torque setting, using a calibrated torque wrench.

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.

It's essential that all wheel nuts are tightened to the specified torque with a calibrated torque wrench. The wheel nuts, fixings and markers should be checked every day before you start your journey.

A warning-lights check is sometimes performed automatically when the ignition is switched on. However, you may need to do this manually by operating a separate check switch. Never start a journey without carrying out this check. If there's a problem, have it repaired before you set off.

You can reduce the chance of a breakdown with routine maintenance and regular checks on your vehicle.

The oil and filter will get dirty in normal use. If you follow the service-interval guidance, your engine will remain protected and properly lubricated, making it less likely to break down.

Bulbs should be replaced as soon as you're aware that they've failed. Carry a stock of all the various bulbs used on your vehicle, so you can repair a fault without delay.

An engine fitted with a turbocharger should be allowed to idle for about a minute before it's switched off. This prevents the turbocharger bearings from being starved of oil.

Energy-saving tyres keep fuel costs down because they have a lower rolling resistance and better grip than ordinary tyres. You should consider this when replacing your tyres.

You should check your tyres as part of your routine check of the vehicle. A damaged tyre - such as one with exposed ply - can have a major effect on your vehicle's handling and will make it a danger to you and other road users.

Fast-moving traffic is passing close by, so wait for the breakdown services to arrive. Their vehicle will provide protection while your vehicle is repaired or recovered.

Whenever you uncouple a trailer, you must work through the uncoupling process methodically. Start by making sure that the brakes are applied on both the vehicle and the trailer.

On a hot day, the fuel in your tank will expand. If this happens when the tank has been filled to the brim, fuel will spill onto the road. This can be very dangerous or even fatal for other road users - especially motorcyclists. Allow for this expansion when filling your tank.

Moisture in the air condenses as the air pressure increases. This moisture can be transmitted around the braking system and is especially dangerous in cold weather. It can lead to ice forming and blocking the valves and pipes.

The operator must have a system in place so that drivers can report defects and have them repaired properly.

Before leaving the cab, it's very important to secure the vehicle by applying the parking brake. After leaving the cab, apply the trailer parking brake.

When refitting a wheel, the nuts should be tightened to the correct torque. They should be rechecked after about 30 minutes if the vehicle hasn't moved, or after 40 to 80 km (25 to 50 miles) of driving.

If you check the engine oil level when your vehicle is standing on a slope, the reading on the dipstick won't be accurate. Park it on flat ground, so the dipstick shows the true level.

DVSA or the police can order an immediate prohibition. The vehicle may be immobilised and you won't be able to drive it until the faults have been rectified. Details are notified to the traffic commissioner. Never use a vehicle that you know is faulty.

Causing excessive smoke is an offence and could contribute to causing an incident or collision. You could also end up creating serious traffic problems if your vehicle breaks down in a difficult location.

As soon as you detect a fault on your vehicle, you must take action. Where faulty brakes are concerned, you need to seek help immediately. Always report minor faults as soon as you detect them. Minor faults can become major ones if they aren't repaired quickly.

You should be familiar with all the warning lights fitted to your vehicle. The oil warning light indicates low oil pressure or lack of oil. If it lights up, report the fault and don't continue until it's been corrected.

Drivers should carry out a walk-round check daily, as part of a routine. They have a legal responsibility to take all reasonable precautions to ensure that legal requirements are met before they drive any vehicle.

You should always allow engines fitted with turbochargers to idle for about a minute before stopping the engine. This prevents the turbine bearings from being starved of oil.

Hitting the kerb at speed can split the tyre or put the steering and suspension geometry out of alignment. Have it checked as soon as possible. A sudden puncture in a front tyre could result in a loss of steering control and a serious crash.

While driving on a building site, bricks, mud or other debris can become lodged between a lorry's double rear wheels. When you leave the site and increase your road speed, anything lodged between the tyres could be thrown out. This flying debris can be a hazard for drivers of following vehicles and can create dangerous road conditions, especially for motorcyclists.

Always have wheel nuts checked soon after their initial tightening. They should be tightened to the torque specified by the vehicle manufacturer.

If your vehicle breaks down, try to stop on the left, facing in the same direction as the flow of traffic. This will help other drivers to see you, as your red reflectors will show to the rear. Don't stop on the pavement, as the weight of the vehicle may damage paving stones and underground services.

In very cold weather, moisture in the storage tanks can freeze. Ice can form in the pipes and this will result in loss of pressure, which could cause brake failure. Make sure that you drain the tanks daily as part of a routine. Most modern vehicles are fitted with automatic bleed valves. Check that they're working properly and that air-drying systems are effective.