Advance warning of a mandatory height restriction ahead
Countdown sign warning of a mandatory height restriction ahead (usually shown in both metres and feet). High vehicles must find an alternative route. This sign is critical for lorries, buses, and caravans. In the theory test it tests your knowledge of height restrictions and the need to check your vehicle’s dimensions before proceeding. Ignoring it can lead to serious damage or a bridge strike.
- Shape
- Rectangular
- Background
- Blue
- Border
- White
- Text type
- Number (Distance)
- Primary symbol
- Other
- Diagram reference
- 818.3
Where you'll see this sign
Approaches to low bridges, tunnels, or multi-storey car parks.
Test yourself on UK road signs
How well do you really know your road signs? New Driver Hub's free mock theory test pulls from official-style DVSA questions and tells you which signs you keep getting wrong.
