What should you do before driving into a tunnel?

While tunnels in the UK are generally safe, incidents still occur. According to data from the Department for Transport, accidents in tunnels make up a small but significant percentage of motorway incidents. Many of these involve collisions due to reduced visibility, improper vehicle spacing, altered traffic flow, or mechanical failures.

Driving through tunnels requires a different level of awareness compared to regular road conditions. Whether you are passing through a short city tunnel or a long motorway one, knowing how to prepare in advance and how to behave inside the tunnel is essential for your safety and that of other road users.

This article outlines the key steps every driver should take before entering a tunnel, from vehicle checks to emergency preparedness, and highlights why these precautions matter.

1. Remove your sunglasses

Before entering a tunnel, it’s essential to remove your sunglasses to ensure optimal vision in the reduced lighting conditions ahead. Tunnels often feature dramatic changes in lighting, transitioning from bright daylight to artificial illumination or even darker sections where visibility is significantly compromised.

Sunglasses, while beneficial for protecting your eyes from glare in bright conditions, can severely impair your ability to see clearly in the dimmer environment of a tunnel. The tinted lenses reduce the amount of light reaching your eyes, making it harder to spot potential hazards, read road signs, or judge distances between vehicles.

The transition from bright outdoor light to the interior of a tunnel already requires your eyes to adjust, a process that can take several seconds. Wearing sunglasses during this adjustment period can leave you temporarily with inadequate vision, increasing the risk of accidents. Remove your sunglasses well before reaching the tunnel entrance to give your eyes time to adapt to the changing light conditions.

Store your sunglasses in a safe, easily accessible location so you can put them back on quickly when exiting the tunnel, especially if you’re returning to bright sunlight conditions.

2. Check your vehicle

While most drivers do not inspect their car just before entering a tunnel, it is advisable to carry out basic checks before setting off on a journey, especially if the route includes multiple tunnels or long motorway stretches. Preparing your vehicle in advance helps prevent breakdowns in confined and high-risk areas.

Before you begin your trip, ensure your headlights and taillights are fully operational. Visibility can be significantly reduced in tunnels, and working lights are essential for seeing clearly and being seen by other drivers. Tyres should also be checked for sufficient tread depth and correct pressure, as both are crucial for maintaining road grip under varying conditions.

It is equally important to confirm that your windscreen wipers are functioning properly, particularly if you expect rain, mist, or damp conditions.

3. Adjust your speed and following distance

Reducing your speed before entering a tunnel is crucial. Tunnels often feature changes in lighting and road layout, and slowing down gives you more time to react. Always adhere to the posted speed limit and be aware of speed cameras.

Maintain a safe distance from the vehicle in front of you. This buffer allows for better reaction time if there’s sudden braking or obstruction ahead. Sudden stops can cause pile-ups in tunnels, where escape routes are limited.

4. Turn on your headlights

UK law requires you to turn on your headlights when entering a tunnel, regardless of the time of day. This improves visibility for you and other drivers. Use dipped beams rather than full beams to avoid dazzling others.

In certain conditions, such as thick smoke or low visibility, using your fog lights may be beneficial. Make sure to turn them off once visibility improves.

5. Stay alert and focused

Driving through a tunnel requires heightened awareness. Avoid using mobile phones or adjusting music settings while inside. Concentration is key, as lighting and noise levels can change abruptly.

Be vigilant for traffic lights, emergency exits, and road signs. These provide critical information in the event of delays, accidents, or diversions.

6. Be ready for emergencies

Although serious incidents inside tunnels are relatively rare, being prepared for emergencies is essential. A breakdown or minor accident can quickly escalate in such an enclosed space, so it is important to know what steps to take if something goes wrong.

If your vehicle breaks down in a tunnel, switch on your hazard lights immediately and try to pull over to a lay-by or emergency bay if one is available. Use the nearest emergency phone to contact tunnel control or emergency services. These phones are typically placed at regular intervals and connect directly to support services.

In the event of a more serious situation, such as a fire or heavy smoke, it may be necessary to evacuate the tunnel. Follow the signs leading to emergency exits, which are clearly marked and often illuminated. Wearing a reflective jacket from your emergency kit will make you more visible to others, especially in low-light conditions.

AUTODOC experts emphasise the importance of keeping a basic emergency kit in your vehicle at all times. This should include a warning triangle, a reflective jacket, a torch, a first-aid kit, and a fully charged phone or portable charger.

Conclusion

Driving into a tunnel presents unique challenges that require extra attention. By preparing your vehicle, adjusting your driving behaviour, and knowing what to do in an emergency, you help protect yourself and other road users. Taking these precautions not only ensures your safety but also contributes to better traffic management in these enclosed spaces.

 FAQs 

Do I need to turn on my headlights when driving through a tunnel?

Yes, it is a legal requirement in the UK to turn on your headlights when entering a tunnel. This helps improve visibility and ensures other drivers can see your vehicle clearly.

Can I stop inside a tunnel if my car breaks down?

If your vehicle breaks down in a tunnel, turn on your hazard lights and try to pull into a lay-by or emergency bay if one is available. If you cannot move the car, stay inside with your seatbelt fastened and use an emergency phone to call for help.

What should I keep in my car in case of an emergency in a tunnel?

It is recommended to carry a basic emergency kit, including a reflective jacket, warning triangle, torch, first-aid kit, and a fully charged mobile phone or power bank.

Are speed limits enforced in tunnels?

Yes, speed limits apply inside tunnels and are often monitored by speed cameras. Always observe posted signs and adjust your speed before entering the tunnel.

Is it safe to use fog lights in a tunnel?

Fog lights can be used if visibility is poor, but they should be turned off if they risk dazzling other drivers. Use them only when absolutely necessary and follow local regulations.