Only change lanes if doing so won't inconvenience another road user. Merging drivers have a responsibility to give way, if necessary, and not force their way onto the main carriageway. Planning ahead will ensure you're prepared to deal with these situations.

The full name of the CMR is the 'Convention on the Contract for the International Carriage of Goods by Road'. You'll need this document to transport goods internationally by road. Of the four copies required, the consignor, consignee and originator all have one copy, and the fourth travels with the vehicle.

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.

All spare sheets and ropes carried on the vehicle must be tied down securely to prevent them falling onto the road, where they may be a hazard for other vehicles.

When following cyclists onto a roundabout, be aware that they might not take the exit you expect them to. Cyclists approaching in the left-hand lane may be turning right. They may not have been able to get into the correct lane due to heavy traffic, so give them room.

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.

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.

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.

Lanes at roadworks often have weight restrictions to keep larger vehicles in the left-hand lane. The lanes through the roadworks are often narrow and therefore not wide enough for large vehicles to pass each other safely. Always look for restriction signs at roadworks. They're usually placed well in advance to give you time to move safely into the correct lane in good time.

Brake fade occurs when the brakes overheat. Good forward planning and correct use of the gears when descending hills, together with proper use of the endurance brake (retarder), can help to prevent brake fade.

When transporting livestock, it's important to limit the amount of space they have to move around. If you allow them to move around freely, it could increase the risk of injury to the animals. It will also affect the stability of the vehicle when braking and cornering, and could even cause the vehicle to tip over.

Warning lights show when there's danger ahead. This includes

• lane closures
• incidents
• fog
• icy roads.

Spray reducers or spray-suppression equipment are attachments fitted around the wheel arches of large vehicles. They effectively trap spray thrown up from the wheels, which would otherwise reduce visibility for other road users.

Never return to the left-hand lane until you're sure that you're well clear of the vehicle you've just overtaken. Don't cut in too soon and don't rely on the other driver flashing you in. Make your own judgement about when it's safe to move into the left-hand lane.

Roof markings on lorries can help police air-support units to identify stolen vehicles. Fleet operators, particularly those that regularly carry vulnerable or dangerous loads, are encouraged to use these markings.

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

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.

Off-road lorry and coach parks are often well lit and patrolled by police or security firms. Never leave your vehicle unlit on a public road or in a lay-by after dark.

Driving at a constant speed for long periods, such as on a motorway, can cause drowsiness. Falling asleep while driving accounts for a significant proportion of vehicle incidents. You should plan and take regular rest stops, but if you feel the onset of tiredness between these breaks, stop and rest in a safe place.

When you see this sign, you must give way to traffic from the opposite direction, regardless of the size of your vehicle.