Certain road layouts, such as steep changes in gradient or level crossings, can cause long, low or heavily loaded vehicles to scrape the road surface.
This sign gives advance warning so drivers can adjust their approach and avoid damage or loss of control.
What this sign means
The sign shows a red triangle with a black symbol of a car whose underside is touching the ground, illustrated with short marks beneath it to represent scraping.
It warns of a change in road level, such as a hump back bridge, dip, or level crossing, where the underside of a vehicle may hit the road if it is low, long, or heavily loaded.
What to do when you see it
Adjust your speed and approach to reduce the risk of grounding.
- Slow down well before reaching the hazard
- Approach any hump or dip at an angle if advised, or straight on at low speed
- Take extra care if driving a low vehicle, a long wheelbase vehicle, or one towing a trailer
- Be aware other vehicles ahead may slow suddenly to negotiate the hazard
How this sign is tested
The theory test may ask you to identify this sign from its symbol and explain what type of vehicles are most at risk.
It can also appear in questions about level crossings or humped bridges, linking the sign to a specific road feature.
Common mistakes
Some drivers assume this sign only applies to lorries, forgetting that cars with low ground clearance or heavy loads can also ground on steep humps or dips.
Others fail to slow down enough, misjudging how quickly the road level changes at the hazard.
Test yourself on this one
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Practise road sign questionsFrequently asked questions
What does the risk of grounding sign show?
It shows a vehicle symbol scraping the road, warning of a change in road level such as a hump or level crossing.
Which vehicles are most affected?
Low vehicles, long vehicles, and those towing trailers are most likely to ground, though heavily loaded cars can also be affected.
What should I do when I see this sign?
Slow down and approach the hazard carefully, taking extra care if your vehicle has low clearance.