Most large vehicles have a rev counter (tachometer) that's divided into coloured bands. This helps you to drive in the most fuel-efficient way and avoid damage to the engine. The green band is the one that gives adequate torque and power with optimum fuel economy.

Debris falling from vehicles can be very dangerous to other road users, so skips need to be covered when they're transported. Falling debris may also cause environmental damage.

The brushes are part of a spray-suppression system. They reduce the amount of water thrown up at the sides and rear of the vehicle. Check them regularly for security. If they become worn, make sure they're replaced.

The marker boards should be red and white. They must be kept clean and independently lit at night and in poor visibility, so that other road users can see them.

The road ahead is at risk from falling rocks and you may also come across fallen rocks in the road

Closed curtains on large empty vehicles can hold the wind. Strong side wind can blow a semi-trailer off course and, in severe cases, can blow the whole vehicle over onto its side. To reduce the risk of this happening, you should tie the curtains open.

The endurance brake (retarder) usually operates by applying resistance, via the transmission, to the vehicle's driven wheels. If the road is slippery, the tyres may lose grip and the wheels will lock.

A lorry loaded like this will be top-heavy and more likely to overturn in high winds or when cornering. If you're only carrying half a load, you should try to carry it on the lower deck.

When passing horses, allow plenty of space, slow down and stop if you need to. Animals are easily frightened by sudden or loud noises and can quickly become uncontrollable, so don't sound your horn or rev the engine.

There's a particular risk when driving between 2 am and 7 am. This is when the 'body clock' is programmed for sleep in most people. There's another, smaller, dip between 2 pm and 4 pm. If you feel that tiredness is affecting your ability to drive, stop in a safe place and rest.

Drivers of buses and coaches with more than 16 passenger seats require a category D licence. Make sure your licence has the correct entitlement for the vehicle you plan to drive.

Chilled foods are transported at temperatures above freezing point. Drivers need to be trained in hygiene procedures and how to operate refrigeration units.

Always look out for road signs, but be especially aware of those that refer to large or heavy vehicles. Get into the habit of checking for signs at junctions. There might be an indication on the junction layout sign. Before you turn, make sure that the road you're using doesn't have any restrictions for the vehicle you're driving.

When carrying high-value goods, you can become a target for thieves. Avoid developing a set routine or pattern. Vary your routes whenever possible to make it difficult for thieves to predict when and where your cargo can be intercepted.

You're responsible for your vehicle, so you should reduce the risk of it being stolen. Plan any lengthy stops for places where your vehicle will be safest, such as a well-lit rest stop at night. Also have an alarm and immobiliser fitted to the vehicle by a security specialist.

Higher speeds will cause more spray to be thrown up by vehicles' tyres - particularly the tyres of larger vehicles and trailers. Always use dipped headlights in poor visibility caused by rain and spray.

While overtaking, you'll need to judge carefully when to return to the nearside lane. Check your left-hand (nearside) mirror to make sure the rear of your vehicle is well clear. You should allow for the length of both vehicles and take into account the speed difference. Don't cut in too soon on the vehicle you've overtaken, and don't rely on signals from other drivers; they may be signalling to someone else.

Every year, there are hundreds of incidents in the UK where vehicles hit railway or motorway bridges. Most involve buses, coaches and lorries. Make sure your route doesn't take you under a bridge that's too low for your vehicle. If you hit a bridge, you'll be putting yourself and any passengers at risk, and you could cause a major disruption to road and rail transport.

In exposed places, such as high-level bridges, viaducts or some motorways, high winds can cause the road to be closed to certain vehicles. If you're driving a high-sided vehicle and high winds are forecast, plan an alternative route in case your intended route is closed.

Lift the pedestrian's leg so that the wound is higher than their heart. This should reduce the flow of blood. Check that the limb isn't broken and there's nothing in the wound before applying pressure over it.

Before driving into a tunnel, you should take off your sunglasses. If you don't, you'll find that your vision is restricted - even in a tunnel that appears to be well lit.

Keep a check in your mirrors as you're driving to make sure that the sheets are secure. Air can force itself under the sheets and work them loose.

Traffic officers don't have enforcement powers, but they're able to stop and direct people on motorways and some 'A' class roads. They only operate in England and work in partnership with the police at incidents. Traffic officers can be recognised by their orange-and-yellow jackets and their vehicles, which have yellow-and-black markings.

If you're involved in an incident that causes damage or injury to a person or property, you must stop. You must also give your details to anyone who has reasonable grounds to ask for them. If you don't do this, you must inform the police as soon as possible and in any case within 24 hours.

The differential allows the drive wheels to rotate at different speeds; this is necessary for the vehicle to negotiate corners and bends. On a slippery surface, however, it can cause problems: if one wheel has less traction, it can spin, resulting in a complete loss of drive. The 'diff-lock' prevents the wheels from turning independently and so helps to stop this happening.

You mustn't park or stop on a road marked with double white lines (even where one of the lines is broken) except to pick up or set down passengers.

Horse riders often keep to the outside of the roundabout even if they're turning right. Give them room in case they have to cross lanes of traffic.

This sign gives you advance warning of a junction where the permanent sign is obscured by roadworks.

In icy or snowy weather, your stopping distance can increase by up to ten times. Because snowy weather increases the distance needed to stop, you must look further ahead and leave an increased safety margin.

It's illegal to drive a vehicle that's emitting excessive exhaust smoke, so you should get the problem fixed as soon as you're aware of it. Excessive exhaust smoke increases pollution and creates a hazard for other road users.

Never attempt to change direction to the right without checking your right-hand mirror. A motorcyclist might not have seen your signal and could have decided to overtake. This action should be a matter of routine.

Elderly pedestrians may have impaired judgement, hearing and/or vision. Be aware that, if they do start to cross, they could take more time to do so.

Don't remove anything sticking to a burn. You may cause further damage and introduce infection into the wound. If you can, douse the burn with clean cold water or other non-toxic liquid for at least 10 minutes.

In icy or snowy weather, your stopping distance can increase by up to ten times. Because snowy weather increases the distance needed to stop, you must look further ahead and leave an increased safety margin.

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.

A loose brake pedal would suggest a serious loss of fluid from the hydraulic system. Don't drive your vehicle until the fault has been checked and fixed by a qualified person.

You should always plan your route. This will ensure you always drive on roads that are suitable for the size and weight of your vehicle. By planning to avoid peak travel times, you can also avoid congestion. This can save you fuel, as well as reducing your journey times.

When air is compressed, moisture condenses and collects in the air tanks. This can find its way along the network of pipes connected to the brakes. In frosty weather, the moisture can freeze in the pipes, blocking them completely. On modern vehicles, the air is dried before it's compressed and the air tanks drain automatically to shed any moisture. On older vehicles, the air tanks need draining manually.

The horn shouldn't be used between 11.30 pm and 7.00 am in a built-up area. The only exception is when another road user is unaware of you and poses a danger.

Forward planning is important whenever you consider overtaking another road user. You should carefully assess the speed of the vehicle you intend to overtake. Remember that your vehicle's speed is limited and this could considerably increase the distance and time needed to complete the manoeuvre safely.

Power-assisted steering operates when the engine is running. If a fault develops, much greater effort is required to turn the steering wheel. Don't attempt to drive a vehicle if you're aware of a fault in the power-steering system.

It's more difficult to judge speed and distance accurately in the dark. Darkness can also hide bends and dips in the road. Plan ahead, and be sure that you have time and space to complete your overtaking safely.

To make sure it's safe, you must use the mirrors well before you make any manoeuvre. For example, you need to use them before moving off, turning, overtaking, slowing or stopping, opening a door, or changing direction, lanes or speed.

If you've been convicted of drink- or drug-driving, statistically you're a risk to yourself and others on the road. For this reason, when you're able to drive again, insurance companies may charge you a high premium to insure your vehicle.

Split-link and iron chains shouldn't be used to secure loads, as they're less reliable than solid-link and steel chains. For more information on the suitability of various-sized steel chains, consult the relevant British Standard (BS) leaflets.

The maximum speed for lorries over 7.5 tonnes maximum authorised mass on a dual carriageway in England and Wales is 60 mph. In Scotland, the limit is 50 mph. Be aware of the speed limits applying to different types of vehicle on particular roads. This is the maximum speed allowed, but it may not always be safe to drive at this speed, because of the weather, volume of traffic and other factors.

In congested tunnels, you should always obey the instructions given by variable message signs and tunnel officials. Listen out for radio announcements and observe the road signs and signals. Keep your distance from the vehicle in front.

The service brake is usually operated by the brake pedal. It's used to control the speed of the vehicle and to bring it to a halt safely. It may also incorporate an anti-lock braking system.

No phone call is important enough to endanger someone's life. If you must be contactable when driving, plan your route to include breaks where you can catch up on telephone messages in safety. Always choose a safe place to take a break.

If you're in a collision, a properly adjusted head restraint can help to reduce the risk of neck injury. However, an incorrectly adjusted head restraint could worsen any damage to your neck.

Your tachograph chart is a legal document; it's a record of your work covering a rolling 24-hour period. Drivers who break the rules are subject to heavy fines and could lose their vocational licence. Altering your tachograph chart with intent to deceive is against the law and could lead to a prison sentence. Similar penalties exist for those who permit such offences.

If you're using a vehicle equipped with an analogue tachograph, you'll need at least one chart for every 24 hours. Your employer should supply you with enough tachograph charts for your entire journey.

Spilt diesel creates a serious risk to other road users, especially motorcyclists. Take care when refuelling and make sure that all filler caps and tank hatches are properly closed and secure.

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.

You must always be aware of the size of your vehicle. Look out for road signs that show a width restriction. There should be an indication of this at the entrance to the road. Don't get into a situation where you have to reverse out of a narrow road because you haven't seen a sign.

Drag is caused by wind entering the cavity of an uncovered tipper. If the cavity is covered, then the drag is reduced.

Misuse of drugs and/or alcohol may lead to the withdrawal of your driving licence. Future insurance premiums will probably increase as well.

Driving at high speed on a wet motorway can throw up dense spray, making it very difficult for other drivers to see ahead. Driving more slowly reduces the amount of spray and this makes it safer for other drivers.

Beware of children playing in the street and running out into the road. If a ball bounces out from the pavement, slow down and stop if necessary. Don't encourage anyone to fetch the ball from the road. Other road users might not see your signal and you might lead a child into danger.

Always allow plenty of time for your journey, in case of unforeseen problems such as punctures, breakdowns, road closures or diversions. You'll feel less stressed and less inclined to take risks if you're not under time pressure.

The car is the most stable of the vehicles shown. However, all vehicles are affected by side wind and buffeting from larger vehicles. Be aware that your speed and road position could cause unnecessary turbulence when passing smaller vehicles.

You'll need to identify the sign in time, so that you can select an appropriate gear.

Horses are easily frightened, so pass them slowly and carefully, giving them as much room as possible. On country roads, expect farm animals, horses, pedestrians and farm vehicles. Always be prepared to slow down or stop.

You must show consideration to other road users. The reactions of older drivers may be slower and they might need more time to deal with a situation. Be tolerant and don’t lose patience or show your annoyance.

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

This traffic sign means no stopping on the main carriageway at any time, not even to set down passengers. However, you may stop in a lay-by.

Always be aware of your limited vision around your vehicle, due to its size and shape. Never move off without checking along the nearside of your vehicle. You should be aware of the possibility of cyclists and motorcyclists getting trapped between your vehicle and the kerb.

If your vehicle catches fire in a tunnel, you should first try to drive it out - but only if you can do so safely.

You should be aware that motorcyclists are likely to be affected by side wind and can be blown into your path. Adjust your speed so that you can stop or take avoiding action safely if necessary.

Using the brakes to control a lorry's speed as it's driven down a hill will cause them to get hot. If they overheat, they can become less effective - a condition known as brake fade. By selecting a low gear, the engine's resistance will slow the lorry. This reduces the demands on the brakes, making them less likely to overheat.

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.

Use your hazard warning lights on a motorway or unrestricted dual carriageway to warn following drivers of an obstruction or hazard ahead. This will alert drivers who may not be able to see the hazard due to the size of your vehicle.

Continuous use of the brakes will cause them to overheat, and in extreme cases they'll become ineffective. When you're going downhill, the momentum of your vehicle will cause you to gather speed very quickly. Use the endurance brake (retarder) and stay in a low gear to reduce the need to use the brakes.

The exit from a motorway is indicated by countdown markers. These are positioned 90 metres (100 yards) apart, the first being 270 metres (300 yards) from the start of the slip road. Move into the left-hand lane well before you reach the start of the slip road.

Plan your journey and take breaks to keep in touch if necessary. When driving on motorways, you can't just stop to use your mobile phone. You'll need to turn off the motorway or wait until you reach the next service area. Avoid being distracted by switching your phone off while you're driving; use the message facility to listen to any calls when you've parked safely.

You should always leave a safety margin between your vehicle and the one in front. This gap will give you a better view of the road ahead. It will also allow you time to react if the traffic in front changes speed or direction.

Before overtaking, you need to make sure it's safe to carry out the manoeuvre. As part of your check, look well ahead for road junctions. You shouldn't overtake as you approach a road junction, because if a vehicle emerges, or has to wait to turn, you could risk a collision.

You need to know the length of your vehicle as well as its weight, height and width. Places where the length of your vehicle may be relevant are

• road tunnels
• level crossings
• ferries
• bridges.

Toucan crossings can be used by cyclists and pedestrians. Some cycle routes lead cyclists to these crossings. Always look out for cyclists, as they're likely to be approaching much faster than pedestrians.

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.

A bus equipped with a speed limiter must also be fitted with a plate showing the speed setting. This must be fitted in an obvious position, where it can be clearly seen.

When turning at a mini-roundabout, it's unlikely that you'll be able to avoid going over the marked area. You should, however, avoid going over the roundabout where possible.

Before leaving your vehicle parked, you must stop the engine. The parking brake must be set and the vehicle should be safe and secure when you leave the cab.

Be especially careful about moving casualties at the scene of an incident. Inexperienced handling of a casualty could cause more injury, or even prove to be fatal. Only move casualties if they're in danger; for example, from fire.

When passing other road users - especially motorcyclists and cyclists - in wet weather, the spray from your vehicle could affect their control. Leave plenty of room as you pass, and look in your left-hand mirror to check that they're still in control.

If you stop for pedestrians and they don't start to cross, be patient. Don't wave them across or sound your horn. This could be dangerous if the driver of an approaching vehicle isn't aware of them. The driver may not have seen or heard your signal, making it very dangerous for the pedestrians to start to cross.

There will be an orange label on the side and rear of the tanker. Look at this carefully and report what it says when you phone the emergency services. Details of hazard warning plates are given in The Highway Code.

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.

It's vital that you give yourself enough separation distance when driving on icy roads - ten times as much as in normal conditions. You should brake gently to reduce the risk of losing control.

When using a lorry-mounted crane, stabilisers should always be used. All drivers should be fully trained and regularly tested on their competence in using stabilisers.

The blue (auxiliary) line isn't used when connecting to a two-line system. Follow the manufacturer's instructions about what to do with this third line.

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.

Plan well ahead and take care if you need to move out or straddle lanes due to the length of your vehicle. Other road users may not understand your reasons for doing this and may try to pass on your left. Check your mirrors before and as you turn. It's better to use extra space on the road you're leaving than to find there's not enough room when you turn in.

You can legally remove your seat belt when carrying out a manoeuvre that involves reversing. Don't forget to put it back on again when you've finished.

Before you make a turn or a change of direction, however slight, you should always check the mirrors. If you intend to turn left, check your left-hand (nearside) mirror first.

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.

Research shows that approximately 40% of SRVIs involve commercial vehicles. The consequences are usually very serious because of the size of the vehicle and the fact that there is no braking before the impact.

Large vehicles can be fitted with various types of endurance brake (retarder). Make sure you're familiar with how the system operates on the vehicle you're using. Don't risk a crash or collision through ignorance.