The tunnel ahead sign shows a black tunnel entrance graphic inside a red warning triangle.
It warns drivers that the road enters an enclosed tunnel structure where light levels change and special safety rules apply.
What this sign means
This sign alerts drivers to an upcoming road tunnel requiring headlight usage and attention to lane signals.
- Red warning triangle
- Black tunnel entrance graphic
- Alerts to enclosed structure, dark lighting, and special traffic controls
What to do when you see it
Switch on dipped headlights before entering, remove sunglasses, turn on your radio for emergency broadcasts, and maintain a safe gap.
- Switch on dipped headlights before entry
- Check fuel level and keep extra distance from vehicles ahead
- Obey variable speed limits and lane control lights
How this sign is tested
Theory exams test headlight rules, distance keeping, and emergency procedures in tunnels.
Common mistakes
Forgetting to switch on dipped headlights or using full-beam headlights which dazzle other drivers in enclosed spaces.
Test yourself on this one
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Practise road sign questionsFrequently asked questions
Which lights should you use inside a tunnel?
Use dipped headlights so your vehicle is clearly visible to others without dazzling them.
What should you do if your vehicle breaks down in a tunnel?
Switch on hazard lights, pull into an emergency layby if possible, turn off engine, and use the tunnel emergency phone.
Why should you tune into local radio in long tunnels?
Tunnel operators broadcast safety and traffic emergency announcements over radio frequencies.