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.

A person who's hysterical may do things that you wouldn't expect. Try to keep the distressed person calm and safe until the emergency services arrive.

If you attempt to move a casualty who has a spinal injury, it could cause further damage. Make sure an ambulance has been called for and talk to the casualty to keep them calm.

To help a casualty who isn't breathing, you should remove any obstructions from their mouth and tilt their head back slightly. These actions will help to keep their airway clear and maintain the correct position if mouth-to-mouth resuscitation is required.

The effects of shock may not be immediately obvious. Try to recognise the warning signs early; prompt treatment can help to deal with it. Symptoms include a rapid pulse, pale grey skin, sweating and rapid shallow breathing.

An engine fire is serious. If the fire breaches the fuel lines, it can easily spread to the fuel tank. If that happens, both the vehicle and its cargo will probably be lost. Therefore, your priority is to shut off the fuel supply.

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.

Vehicles carrying dangerous goods and other materials that may pose a hazard are subject to detailed emergency procedures. These procedures must be followed. Appropriate fire-fighting equipment must be available and the driver must be trained in its use.

If your vehicle catches fire in a tunnel and it can't be driven, stop on the side of the road, as far away from passing traffic as possible. Turn off the engine and warn other traffic by switching on your hazard warning lights.

Prompt treatment can help to deal with shock. Warning signs to look for include rapid pulse, sweating, pale grey skin, and rapid shallow breathing. While waiting for help to arrive, keep the casualty warm and comfortable, and speak reassuringly to them.

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 entering a tunnel, you should switch on your dipped headlights; these help you to see and be seen. In many tunnels, using headlights is a legal requirement. You should also remove your sunglasses before you drive into a tunnel.

Vehicles that carry dangerous goods have badges displayed on the side and rear. The badges are orange and show the type of material that's being carried. Make a note of this and report it to the emergency services when you contact them.

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.

Whenever possible, call the emergency services first. If you're able to give first aid, remember DR ABC. Check for Danger, then check the casualty for a Response. Check the Airway, and try to establish Breathing by gently lifting the chin up and forward. Give Compressions if necessary. Try to stop any severe bleeding. If you feel you aren't capable of carrying out first aid, consider taking some training. It could save a life.

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.

Warn other traffic of the incident, without putting yourself or others at risk. Once the danger of further collisions is dealt with, call the emergency services. While you're waiting for them to arrive, keeping casualties or witnesses calm is important, but never offer a cigarette because of the risk of fire.

At the scene of an incident, if there are any casualties who are in contact with live electricity, don't touch them with your hands - even if you're wearing gloves. You should use a dry, non-conducting item, such as a wooden sweeping brush or plastic spade. You mustn't give first aid until you're sure the electrical contact has been broken, otherwise you'll be putting yourself in danger.

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.

If you don't give your name and address at the time of an incident, report it to the police as soon as you can, or in any case within 24 hours. If any other person is injured and you don't produce your insurance certificate to the police at the time of the incident, or to any other person who has reasonable grounds to request it, you must also

• report the incident to the police as soon as possible, or in any case within 24 hours
• produce your insurance certificate to the police either when reporting the incident or within seven days (five days in Northern Ireland) at any police station.

If it's possible, and you can do so without causing further danger, it's safer to drive a vehicle that's on fire out of a tunnel. The greatest danger in a tunnel fire is smoke and suffocation.

Someone who has been involved in or witnessed a crash will be in no mood for humour. The best way to calm them is by remaining calm yourself, and talking quietly and firmly to them.

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.

If you're trying to resuscitate someone, it's important that you don't give up on them. Make sure that someone has called the emergency services and continue trying to resuscitate the casualty until medical help arrives.

If you stop to give help at an incident and there are casualties, don't move injured people unless there's further danger. Keep them warm, comfortable and calm. Don't give them anything to drink.

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 warn other road users that there has been a incident. You can do this by displaying an advance warning triangle or by switching on hazard warning lights or other lights. However you choose to warn people of the incident, make sure it doesn't put you or others at risk.

Immediate treatment can help to reduce the effects of shock. Reassure the casualty and try to keep them warm and comfortable. Only move a casualty if it's necessary for their safety.

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.

It's very important to know the correct fire extinguisher to use. They'll carry a coloured label or badge telling you their contents. Make sure you learn which extinguisher is which, as using the wrong one could be dangerous and may spread the fire further. For example, you should never use a water extinguisher on burning oil.

At the scene of an incident, the first priority is to prevent any further collisions by warning traffic. You can warn other traffic by switching on hazard warning lights or displaying an advance warning triangle, or by any other appropriate means.

The priority when dealing with an unconscious person is to make sure they have a clear airway and can breathe. Stay with the casualty and make sure someone rings for an ambulance.

Motorway phones are free and easily located. You should face the oncoming traffic while using them, so that you can see approaching vehicles.

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.

If your vehicle is involved in a traffic incident, you must stop. Follow the guidance set out in The Highway Code if there's injury or damage to any other person, vehicle or property.

If your vehicle breaks down in a tunnel, it could present a danger to other traffic. First, switch on your hazard warning lights. If there are passengers in your vehicle, take them to the nearest exit point. You should then call for help from an emergency telephone. Don't rely on being found by the police or being seen by a CCTV camera. The longer a vehicle stays in an exposed position, the more danger it poses to other traffic.

If there's nothing embedded in the wound, you can control the blood loss by applying pressure to the wound and raising the leg if possible.

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.

At the scene of an incident, first make sure there's no danger of further collisions or fire before dealing with any casualties. The priority when dealing with an unconscious person is to make sure they can breathe. This may involve clearing their airway if they're having difficulty or there's an obvious obstruction. Don't remove a motorcyclist's helmet unless it's essential, as you could cause them serious injury.

Cold water will cool the burning tissue and help prevent further damage. It will also reduce swelling, minimise shock and alleviate pain. Use water, or any other liquid, that's clean and non-toxic.

If you're trying to resuscitate a casualty, don't give up until medical help arrives. Never assume that someone's dead. People who aren't breathing can survive longer than you may imagine when given chest compressions and mouth-to-mouth resuscitation.

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.

If you're the first to arrive at an incident, further collisions and fire are the immediate concerns. Switch on your hazard warning lights to warn other traffic. Stop any running vehicle engines to reduce the risk of fire. Don't assume that someone else has called the emergency services - do it yourself. Don't move casualties trapped in vehicles unless they're in danger.

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.

On the approach to many tunnels, a board will indicate a local channel or radio frequency that you should tune into. This should give a warning of any incident or congestion in the tunnel ahead. Severe loss of life has occurred in tunnel fires. Getting advance warning of any problems ahead will help you to take appropriate action in good time.

You can help someone suffering from shock by talking to them and reassuring them confidently. Don't leave them alone or give them anything to eat or drink.

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.

At a traffic incident, the danger of further collisions and fire needs to be dealt with first. Then you should deal with injuries in this order: airway, breathing, compressions and bleeding. Don't remove a motorcyclist's helmet unless it's essential to do so.

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.

Gently tilt the unconscious person's head to clear their airway. Check for at least 10 seconds that the casualty is breathing by looking for movement in the chest, listening for sounds and feeling for breath on your cheek. Get someone to call the emergency services.

Make sure you or someone else has called the emergency services. Check the casualties and, if you feel able to give first aid, do so. Alternatively, ask any bystanders if they can help.

The priority when dealing with an unconscious person is to make sure they have a clear airway and can breathe. Stay with the casualty and make sure someone rings for an ambulance.

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.