Information sign
Low bridge ahead sign
What does the Low bridge ahead sign mean?
Advance warning of a mandatory height restriction ahead, so high vehicles can take another route in good time.
Also known as: Height restriction ahead
What it means
A height restriction ahead, at the distance shown.
The sign gives advance warning of a mandatory height restriction ahead. It may include an arrow if the restriction is on a side road.
If your vehicle is taller than the limit, take another route now rather than at the bridge.
Where you'll see it
Well before low bridges, at a point where high vehicles can still divert.
Rules to know
Advance warning of a mandatory height restriction ahead; the sign may include an arrow if the restriction is on a side road.
Know Your Traffic Signs, p. 25
Common mistakes
Mistake: Carrying on to the bridge to see if you fit.
Instead: Divert when you see the advance sign.
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© Crown copyright. Free to reuse under the Open Government Licence v3.0, as long as the sign is reproduced accurately and not in a misleading context.
Related signs
Used with
Maximum height
Regulatory sign
The height limit itself.
See also
Maximum headroom
Warning sign
A warning triangle showing headroom.
More information signs
All information signs
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- Know Your Traffic Signs (Department for Transport, Sixth edition, 2023), Low bridge signs, p. 25
Sign image: Department for Transport, Traffic sign images (diagram 818.3). © Crown copyright, reused under the Open Government Licence v3.0.
Last reviewed 11 October 2026. This page explains the sign in our own words; for the full rules, see The Highway Code. How we source and check content