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.

In the darkness, it will be difficult to assess the road ahead - especially if there are bends or hills, which may prevent you from seeing oncoming vehicles.

Fluids carried in tankers can move in waves as the vehicle's speed or direction changes. This happens particularly when you brake and then ease off the pedal; the moving wave of liquid causes the vehicle to surge forward. Baffle plates are designed to reduce this surging effect.

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.

Vehicles overtaking in the right-hand lane may return to the centre lane when they've finished their manoeuvre. You should look for this before starting to pull out. Don't rely on the size of your vehicle to claim right of way.

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.

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.

This sign gives a clear instruction. You should prepare to negotiate a left-hand turn.

The only time you may use hazard warning lights while driving is when you're on an unrestricted dual carriageway or motorway and you want to warn other drivers of a hazard or obstruction ahead. Only use them for long enough to make sure your warning is seen.

The choice of restraint will depend on the load. For example, ropes are unsuitable for loads such as steel plates, as there's a danger of sharp edges shearing the ropes. For steel plates, chains must be used with a suitable tensioning device.

The cyclist may not be able to get into a right-hand lane due to heavy traffic. Give them room, as they may not be taking the exit you expect.

If you become unwell, it will affect your ability to concentrate. You must be fully alert and ready for any hazards that might occur while you're driving. Stop in a safe place and call for help. You may have to call out a relief driver to complete the journey for you.

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.

Drivers of vehicles carrying dangerous goods are required to hold an ADR driver training certificate. This certificate is valid for five years and is issued by DVLA when you've attended an approved course and successfully completed the examination.

Endurance brakes or 'retarders' help to control a vehicle's speed. They operate by applying resistance to slow the vehicle without using the wheel brakes, so avoiding brake fade. The methods used include: increased engine braking, exhaust braking and transmission-mounted devices.

Operators must set up an 'effective system' to prevent the carriage of illegal immigrants. This should include documentation with advice on vehicle security and a list of checks to be made. These papers should be produced immediately if an immigration officer asks to see them.

As well as headlights and tail lights, large vehicles have additional lighting to help other road users see the size of the vehicle. All lights should be clean and working properly. Driving at night when your vehicle is poorly lit is dangerous for you and other road users.

Drivers' hours and rest periods are controlled in the interests of road safety. A driver's daily rest period should normally be 11 hours, but this may be reduced to 9 hours up to three times between weekly rest periods. It's a serious offence to break these rules and anyone doing so is liable to a heavy fine and even imprisonment.

After overtaking, check your nearside mirror carefully before moving back to the left. Don't rely on the other driver flashing their headlights, because only you can make the decision that it's safe.

At hump bridges, there's a risk of long vehicles grounding. If you aren't sure whether the floor of your vehicle will clear the bridge, find another route.

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.

You should always check your nearside mirror before any change of direction. Be alert for cyclists and motorcyclists who don't realise the potential danger involved in trying to squeeze through on your nearside when you're waiting at a junction.

Local-authority environmental health departments check vehicles' exhaust emissions. They have the power to prosecute the driver and the operator, as do enforcement bodies such as DVSA.

Continually using the brakes could cause them to overheat. When that happens, they become less effective. This is called brake fade, and it occurs most often when the driver has to control the vehicle's speed on a long downhill gradient. To help prevent brake fade, use the endurance brake (retarder) and a lower gear to keep the vehicle's speed in check, rather than the wheel-mounted brakes.

To work out your vehicle's payload, use the following formula: maximum authorised mass (MAM), minus tare weight, equals payload. This is the maximum weight your vehicle can carry.

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.

Short-wheelbase vehicles will bounce more noticeably than some long-wheelbase vehicles when empty. This can affect braking efficiency and all-round control.

If your vehicle is too long to fit into a passing place, you may need to wait opposite one. This will allow a following or approaching driver to pass. When you use this type of road, you need to plan and look well ahead to avoid meeting another road user at an inappropriate place.

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.

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.

Slow down and be ready to stop if you see animals in the road ahead. Animals are easily frightened by noise and by vehicles passing too close to them. Stop if signalled to do so by the person in charge of the animals.

An unladen vehicle that also has high sides will be vulnerable to the effects of strong side wind. An evenly distributed load will help to keep the vehicle more stable, but the higher the vehicle is, the more it will be affected. Be aware that such a vehicle may become unstable or difficult to control in windy conditions.

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.

You should tell telephone companies about your intended route when planning the movement of loads over 5.25 metres [17 feet 6 inches] high. You should tell them in plenty of time before making the journey.

High-value cargoes are often targeted by thieves. Operators are recommended to seek advice from their local crime-prevention officer to help prevent their vehicles and loads from being stolen.

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.

Traffic-calming measures are becoming more common. Look out for signs warning you of humps in the road ahead. If necessary, change your route rather than take risks.

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.

At the scene of an incident, you should tell your passengers what has happened, while reassuring them that they're not in danger. Explain to them that the emergency services are dealing with it and they should remain on the coach.

Some bus lanes operate only during peak hours and other vehicles may use them outside these hours. Make sure you check the sign for the hours of operation before driving in a bus lane.

Where a motorway has a steep uphill gradient, slow-moving, large vehicles might get in the way of other traffic. An extra lane on the left may be provided for these slow-moving vehicles. It allows faster-moving traffic to flow more easily.

Goods and passenger vehicles with a MAM of more than 7.5 tonnes, those required to be fitted with a speed limiter, and vehicles towing trailers must not use the right-hand lane on a motorway with more than two lanes, unless there are exceptional circumstances.

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.

The red emergency line is common to both two-line and three-line braking systems. Always set the parking brake before disconnecting any brake line.

Current legislation requires all operators to set up an 'effective system' to help prevent the carriage of illegal immigrants. This should include vehicle security and checking using a checklist. Failure to do this will incur penalties.

The closer you are to the vehicle in front, the less you'll be able to see of the road ahead. You must be aware at all times that you won't be able to see all around your vehicle. This is why you must have an excellent mirror routine and constantly update yourself on what's going on around you.

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.

An endurance brake can help to control your speed on long downhill slopes without using the service brake. Reducing the use of the service brake helps to prevent the brakes from overheating and reduces the risk of brake fade.

If you're taking medicine or drugs prescribed by your doctor, check that they won't affect your driving. If you forget to ask when you visit the surgery, check with your pharmacist.

Jack-knifing occurs when the tractor unit is pushed by the semi-trailer pivoting around the coupling (fifth wheel). This is more likely to occur with an unladen vehicle.

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.

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.

Whenever you see this sign, take extra care with these very vulnerable road users.

Many vehicles are very powerful and can maintain speed even when climbing a gradient. Even if your vehicle is capable of maintaining speed, you can still use the crawler lane to make it easier for other road users to overtake safely.

All drivers should play their part to protect the environment against traffic pollution. Make sure the vehicle you drive is properly maintained. Report any defects, such as excessive exhaust smoke, as soon as you can.

A SORN allows you to keep a vehicle off the road and untaxed. The SORN remains valid until the vehicle is taxed, sold or scrapped. If you buy a vehicle that has a SORN, the SORN will finish as soon as you buy it. You'll need to make a new SORN if you want to keep the vehicle off the road and untaxed.

Buffer lanes are often found in places that are frequently subjected to high winds. Examples include high-level bridges, high-level roads, exposed viaducts and exposed stretches of motorway. Listen to the weather forecast, which should tell you of any need to re-plan your route.

White boxes allow you to unload at any time, but during the day the length of stay is restricted. You should check nearby signs for the specific times. At other times, when it's not so busy, there may not be any restrictions on parking.

The national speed limit for a goods vehicle exceeding 7.5 tonnes on a single carriageway road in England and Wales is 50 mph. In Scotland, the limit is 40 mph. The national speed limit varies for different vehicle categories. You must know the limit that applies to the vehicle you're driving.

Only overtake when it's safe to do so, and don't use the size of your vehicle to intimidate approaching traffic. When overtaking a cyclist, leave plenty of room and, before returning to the left, check in your nearside mirror to make sure you've passed them safely.

Learners might take longer to react to traffic situations. Don't unnerve and intimidate them by driving up close behind.

The risk of fire will be reduced if all fuel supplies are switched off. However, don't put yourself or your passengers at any risk. If there's a fire, call the fire service.

The driver of a passenger-carrying vehicle needs to know the vehicle's limits. These include its weight, height, width and length, and its seating and standing capacity. The unladen weight should be displayed on the nearside of the vehicle.

Air deflectors reduce wind resistance by streamlining the vehicle. They're most effective when there's a headwind. The streamlining also reduces the vehicle's fuel consumption.

Pedestrians use push-button controls to activate the signals. Pelican crossings have no red-and-amber stage before green. Instead, they have a flashing amber light. This means you must give way to pedestrians on the crossing, but you may proceed if the crossing is clear.

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.

All vehicles over 7.5 tonnes maximum authorised mass must have markings on the rear of the vehicle. These markings are rectangular and are coloured red and yellow. They're there to inform other road users of the characteristics of your vehicle. The markings should be kept clean so that they can be seen clearly at all times, especially at night and in poor visibility.

Some exposed places are frequently subject to high winds. These include high-level bridges and roads, viaducts and some motorways. Check the weather forecast and plan an alternative route. Remember, you're responsible for your passengers' safety. Don't ignore warnings of severe winds.

These markings are found on the road outside schools. Don't stop or park on them, even to set down or pick up children. The markings are to make sure that drivers, riders and children have a clear view.

If you're involved in an incident in a tunnel, be aware of the danger this can cause to other traffic. You should immediately switch on your hazard warning lights and switch off your engine.

Make sure the locking mechanism is secure by selecting a low gear and attempting to move forward. Apply the parking brake again before leaving the cab. Connect the 'dog clip' to secure the kingpin release handle.

Under EU rules, the maximum number of hours that you can drive in any two consecutive weeks is 90 hours. These don't have to be split evenly, but the total amount of driving time in any one week mustn't exceed 56 hours. Don't exceed your driving hours; heavy fines can be given to drivers who break the law.

When passing through immigration control, you should have a list of all your passengers. They must all be accounted for.

It can be frustrating and worrying to find your planned route is blocked by roadworks or diversions. If you've planned an alternative, you'll feel less stressed and able to concentrate fully on your driving. If your original route is mostly on motorways, it's a good idea to plan an alternative using non-motorway roads. Always carry a map with you just in case you need to refer to it - but stop driving before you do so.

Look well ahead and be ready to deal with any hazards you see coming up, such as animals in the road. Horses are easily scared by the noise of an engine and the size of your vehicle may also be intimidating. Approach them as slowly and quietly as you can.

Even though there are no restrictions, make sure that you park where you won't cause an obstruction or endanger other road users.

The sign prohibits buses and coaches with more than eight passenger seats and so doesn't apply to you.

A pelican crossing that goes straight across the road must be treated as one continuous crossing even if it has a central island. The lights controlling the crossing show to both directions of traffic. You must give way to pedestrians who are still crossing when the amber light is flashing.

Major roadworks often cause complicated diversions for large vehicles. Drivers may be advised to follow a special symbol until the original road can be rejoined. Look for the yellow-and-black symbols in these shapes:

• square
• triangle
• diamond
• circle.

They'll often be shown with additional information and will help guide you around the diversion.

Suspension faults may result in road damage. Road-friendly suspension reduces the impact on the environment, the road surface and under-road services.

Driving with the rev counter in the red band will cause the engine to wear prematurely and can lead to expensive repairs. This could result in the vehicle being off the road for some time.

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.

When you have to straddle the lanes at small roundabouts or junctions, always signal in good time. Be alert for inexperienced road users who may, without realising, put themselves into a dangerous position.

Give way to buses whenever you can do so safely, especially when they signal to pull away from bus stops. Look out for people who have left the bus and wish to cross the road. Also look for people rushing to catch a bus: they may be more concerned about catching the bus than watching for traffic.

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.

If possible, lay the casualty down. Raising the arm above the level of the heart will reduce the flow of blood. Check that the limb isn't broken and that there's nothing in the wound before applying pressure over it.

HMRC can check the type of fuel you're using, and the type and legality of your load. Red diesel is dyed gas oil with a lower tax than regular diesel. It can only be used in agricultural and construction vehicles (such as tractors). Red diesel mustn't be used in freight transport.

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.

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.

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.

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.

Road-friendly suspension reduces the vibration caused by the impact of the wheels on the road surface.