Traffic queues on the motorway are fairly common, often due to the volume of traffic at peak times or to incidents. If you see a queue of stationary traffic ahead, switch on your hazard warning lights for a short while to warn those behind you of a hazard ahead.

Be aware of, and obey, all speed limits. On a motorway, any lorry that's articulated, towing a trailer, or over 7.5 tonnes mustn't exceed 60 mph (96 km/h).

Motorcyclists can ride through narrow gaps in traffic and generally don't take up as much room as a car. However, other factors, including the road surface, can affect their stability. Give them an extra safety margin whenever possible.

As items are unloaded from the rear of the vehicle, weight will be transferred to the front axle. Take care that this axle doesn't become overloaded. You may need to redistribute the load.

Red Routes operate in many busy cities and are designed to ensure the route has no obstructions to cause delays during peak periods. Road signs and red road markings identify roads where Red Route waiting and loading restrictions apply.

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.

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.

Some highly dangerous chemicals have to be transported at prescribed temperatures. Drivers must be fully trained in the use of these specially designed, temperature-controlled vehicles.

Take care if you're driving an empty high-sided vehicle when it's windy. Watch for places where the conditions could suddenly change, such as a gap between buildings or when passing under a bridge. Reduce your speed and stay alert for other road users who are also affected by these weather conditions.

If your vehicle is over 17 metres (55 feet) long and you wish to cross a level crossing, you must stop before the crossing and telephone the signal operator.

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.

Leaving the filler cap off, or not properly securing it, could result in a spillage of diesel onto the road. Because diesel is slippery, this would be a major hazard, so make sure to correctly secure the filler cap after use.

Driving slowly will give you better control of your vehicle. By using a high gear, you reduce the chance of your wheels spinning and skidding on the snow.

Load security is one of the many responsibilities of the driver. When choosing a site to park your vehicle overnight, you should always look for a location that's legal and well lit. Many allocated lorry parks are patrolled by the police or security firms.

The entrances to roundabouts are often worn. This can make the surface slippery, especially when it's wet. You should plan your approach and brake in good time.

This is the sign for a tram. These vehicles are powered by electricity and reduce the emissions released into the environment. As they can carry many people, they can help to reduce the number of other vehicles on the road.

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.

Too much weight on an axle can reduce braking efficiency and cause brake fade. As well as being dangerous, exceeding the axle weight limit is an offence that can result in prosecution.

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.

To increase stability and reduce the risk of the trailer wheels lifting when turning, it's preferable to locate part-loads over the rear axle(s).

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.

If there's a bend just before a level crossing, you may not be able to see the level-crossing barriers or waiting traffic. These signs give you an early warning that you may find these hazards just around the bend

If you're following cyclists onto a roundabout, be aware that they might not take the exit you expect. Cyclists approaching in the left-hand lane could be turning right but may not have been able to get into the right-hand lane. Give them plenty of room.

You must be able to stop safely in the distance that you can see to be clear ahead. This will be the distance illuminated by your headlights or by street lights and will generally be less than you can see in daylight.

In slow-moving traffic, particularly on dual carriageways or motorways, always be on the lookout for motorcyclists who approach from behind and filter through narrow gaps between vehicles.

Sometimes other drivers or riders make a mistake. If this happens, try not to let it worry you. Don't react by sounding the horn, flashing your headlights or shouting at the other driver; it won't help the situation. A professional driver will remain calm and stay focused on their driving.

Good forward planning can help you keep other road users out of trouble. Information to help you do this is available if you look for it. Watch for clues: for example, a motorcyclist taking a 'lifesaver' look over their shoulder could be about to change direction.

In England and Wales, vehicles exceeding 7.5 tonnes maximum authorised mass are restricted to a maximum of 50 mph on single carriageway roads. In Scotland, this speed limit is 40 mph.

SRVIs are more evident in young male drivers, who tend to ignore or deny how they're feeling. The greatest risk is between the hours of 2.00 am and 7.00 am, when the body clock is in a trough. Make sure you take sufficient rest breaks and don't ignore feeling sleepy.

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.

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.

If your suspension is damaged, all the weight of the vehicle compresses the road and anything located below it. The vibrations travel through the ground and can also damage surrounding buildings.

The railway authority needs to know immediately if one of their bridges has been hit. You'll need to tell them the number of the bridge so they can identify it. The railway authority will then take action to prevent railway passengers from being put at risk.

If your vehicle hits a bridge, you must report it to the police. If a railway bridge is involved, you must also report it to the railway authority. The phone number is usually shown on or near the bridge.

It's important to keep a safe distance from the vehicle in front at all times. This still applies in congested tunnels, even if you're moving very slowly or have stopped. If the vehicle in front breaks down, you may need room to manoeuvre past it.

As well as a height restriction, the tunnel may have a restriction on the available width of headroom for high vehicles. The advance warning gives you the opportunity to find another route if your vehicle is too high or wide to drive through the tunnel.

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.

Driving in a fuel-efficient manner means that you plan well ahead for hazards and react in good time. This can save fuel and is therefore good for the environment.

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.

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.

In windy weather, exposed stretches of road may have lane closures or there may be diversions for some types of vehicle. Consider this when you're planning your journey; delays will add to your driving time.

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.

While you're using a phone, your attention will be divided between the call and the road. This means you're unable to take in all that's happening around your vehicle. You need to be concentrating on your driving all of the time, and especially when dealing with a hazard.

Correctly adjusted air deflectors will save fuel. They should be adjusted to guide the airflow over the highest point at the front of the trailer or load and body.

When you have to slow down or stop, you should always avoid harsh, late braking. This is particularly important on icy or slippery roads, where you need to brake gently and in good time to make sure you keep control of your vehicle.

Theft of vehicles is common. You're responsible for the safety and security of your vehicle and trailer. Try to avoid leaving any trailer unattended unless it's on approved secure premises.

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.

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.

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.

You'll generally see this sign at the approach to a pedestrian-only zone.

Concentration and good judgement are needed to be a good, safe driver. You're strongly advised not to drink any alcohol before driving. Alcohol can stay in your system for 24-48 hours, so you should also consider your intake the day and night before driving.

The flashing amber light allows pedestrians already on the crossing to get to the other side before a green light shows to the traffic. Be aware that some pedestrians, such as elderly people and young children, need longer to cross. Let them do this at their own pace.

Avoiding busy times means that you're not adding needlessly to traffic congestion. Other advantages are that you'll use less fuel and you may have an easier journey, making you feel less stressed.

Don't move a casualty who's in a safe place, as this could worsen any injury they may have. Only move a casualty if they're in danger - for example, from passing traffic. You may also need to move them if you need to give lifesaving first aid, such as clearing their airway.

Roll-over' usually happens as a result of the inside rear wheels of an articulated vehicle starting to lift when the driver changes direction sharply. This tends to happen when a driver is changing direction to leave a roundabout. If the load moves during the change of direction, the vehicle is increasingly at risk of rolling over. The problem often involves vehicles carrying fluids in bulk.

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.

There are heavy fines for those convicted of bringing illegal immigrants into the UK. This can mean a fine for each illegal person carried. The fine can be imposed on each 'responsible person', including the vehicle driver, owner and hirer.

If you become aware that any part of your load is insecure, you must stop as soon as it's safe to do so. Resecure the load before continuing your journey. If this isn't possible, then you must seek assistance. Don't take risks.

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.

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.

The headroom under bridges in the UK is at least 5 metres [16 feet 6 inches], unless otherwise stated. Where the overhead clearance is arched, this headroom is normally only between the limits marked.

It's essential to know the height of your vehicle before setting off. This should be clearly marked, usually in the cab, and visible from the driving position. Look out for restrictions that you may not have seen on a map - they may be temporary.

Moving a casualty could cause further injury, so it's important that this is only done if there's danger to them where they are.

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.

Where a motorway has a long or steep gradient, slow-moving large vehicles might get in the way of other traffic. To help the traffic flow, an extra lane - called a crawler lane - is sometimes found on these gradients. This helps the traffic to flow by providing the slower heavy vehicles with a dedicated lane on the left.

The amber light means stop. You may only go on if the light changes to amber after you've crossed the stop line or when you're so close to the line that stopping might cause a collision. The amber light is followed by the red light. You must wait behind the stop line until the green light shows.

The flashing amber lights are switched on to warn you that children may be crossing near a school. Drive slowly and be prepared for children running into the road.

If you see a vehicle with a green flashing light, it will be a doctor on an emergency call, so give way by pulling over and letting the vehicle pass. But don't just stop suddenly - choose a safe place as soon as you can to let the doctor's car pass safely.

Rain, combined with oil, rubber particles, dirt and debris on the road surface, reduces the tyres' grip on the road. It can be especially slippery when it rains after a long dry spell.

Most incidents happen as a result of a lapse in concentration. Don't let this happen to you. If you start to feel tired, you won't perform as well as you should. Your reactions will slow down, and your anticipation and judgement of hazards will become flawed. If you feel tired, stop and rest as soon as it's safe to do so.

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.

This sign is shown where slow-moving vehicles would block the flow of traffic. However, if you need to slow down to avoid an incident, you should do so.

Signal if necessary and move back to the left as soon as it's safe to do so. Don't drive for long distances in the centre or right-hand lane unnecessarily.

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.

Air-brake systems rely on an engine-driven compressor to keep the reservoir tanks at their operating pressure. Coasting downhill and relying on the brakes to control your speed could result in the loss of sufficient air pressure to operate the brakes effectively.

Double red lines indicate that you're on a Red Route and in a no-stopping area. Red Routes also have single red lines, with signs showing the times that restrictions are in force. There are also parking and loading boxes, which have signs explaining the restrictions that apply.

On smart motorways, the hard shoulder can be used as a running lane when a speed limit is shown above it. However, a red cross above the hard shoulder means that this lane shouldn't be used, except for emergencies and breakdowns.

Allow the cyclist plenty of room. Give them space and be prepared for them to change direction. To stay safe, they may travel around the roundabout in the left-hand lane.

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.

When traffic is heavy, plan well ahead so that you don't block crossings. Leave them clear so that pedestrians can cross safely.

There are times when, due to the size of your vehicle, you'll have to take up part of another lane. If you need to do this, make sure that you use effective observation all around. Be aware that other road users might not understand the reasons for your position on the road. You should signal your intentions and take up your position in good time.

Always indicate your intentions in good time; this will allow others time to alter their speed and course if necessary. Always check your blind spots before changing lanes.

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.

When you're driving on a smart motorway, speed limits will show above each lane. These limits are shown inside a red circle and must be obeyed. A red cross will usually appear above the hard shoulder. When the hard shoulder is being used as a running lane, an appropriate speed limit will be displayed instead.

It's your responsibility to make sure that the vehicle's load is spread evenly, to avoid overloading individual axles. Overloading carries severe penalties for the driver and operator.

When you're driving a long vehicle, you'll often need to straddle lanes to turn into narrow side roads. When you do this, watch out for smaller vehicles - especially motorcycles and cycles - trying to squeeze past on your inside.

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.

Side markers must be displayed if your load is over 2.9 metres [9 feet 5 inches] wide. Make sure that they're clearly visible, at both the front and rear, and that they indicate the actual width of the projection.

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

Rain makes the road surface slippery and reduces tyre grip. Doubling your separation distance should allow you the extra time and space you'll need to slow down and stop safely.

Standing on or near the edge of the carriageway is very dangerous. Your priority is to alert the emergency services by using an emergency roadside telephone. This connects to an operator, who'll get help out to you as soon as possible. In most cases, this is preferable to using a mobile phone, as it will show the operator your precise location.

Puffin crossings have sensors that detect when pedestrians are using the crossing. The sensors control the timing of the traffic lights, and this means that there's no flashing amber phase as there is with a pelican crossing.

The parking brake must always be set whenever you leave the vehicle. It's an offence not to leave your vehicle properly secured.

Take care; it's not worth taking risks. Always check with your doctor to be absolutely sure. The medicine may have an effect on you later in the day and for longer than you think.

It's illegal to use a hand-held phone while driving. When you've stopped in a safe place, you can concentrate on your call or message. Using a phone while driving means you won't have full control of your vehicle. This could result in a collision, with serious or even fatal consequences.

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.

As you turn a corner, the hanging meat carcasses will all swing to one side of your vehicle, adding extra pulling force towards the outside of the curve. The faster you turn a corner, the greater this force will be. After the corner, the carcasses will continue to swing back and forth, like pendulums, making the vehicle unstable.