Height limit sign: what it means
The height limit sign means no vehicle taller than the height shown may go past it. It is an order: an overheight vehicle must not pass.
What does the height limit sign mean?
Know your traffic signs says no vehicles over the height shown may pass the sign, and that the height is shown in metric and imperial units. At non-arch bridges this mandatory sign may be used, and it is unlawful for an overheight vehicle to pass one.
Quick quiz
What does the sign at the top of this page mean?
- No vehicles taller than shown.
- Low bridge ahead: the height shown is the clearance.
- No vehicles wider than shown.
Show answer
A. No vehicles taller than shown. No vehicles over the height shown may pass the sign (Know your traffic signs). Source: Know your traffic signs: low bridge signs, GOV.UK; Know your traffic signs: regulatory signs, GOV.UK; Traffic sign images, Department for Transport, GOV.UK
Where will you see it?
On and in front of low bridges, and before structures such as car park entrances and canopies.
What should you do?
Know your vehicle’s height, including any load, roof box or bikes on the roof. If it is higher than the sign, find another route before you reach the bridge.
What do people get wrong?
Thinking it is only a warning. The red circle makes it a ban; the triangle with a height is the warning version.
Common questions
What is the difference between the round and the triangular height sign?
The red circle is an order: no vehicles over that height. The triangle warns of the maximum headroom (Know your traffic signs).
Why are both metres and feet shown?
Newer signs show both. Older signs in imperial units only will be replaced when they reach the end of their life (Know your traffic signs).
Compare with
Maximum headroom signLow bridge ahead: the height shown is the clearance.
Width limit signNo vehicles wider than shown.
Want to test someone else? Play a road-sign quiz with friends and family.
Sources
Checked on 3 November 2026 against Know your traffic signs (low bridge signs; regulatory signs).
- Know your traffic signs: low bridge signs, GOV.UK
- Know your traffic signs: regulatory signs, GOV.UK
- Traffic sign images, Department for Transport, GOV.UK
Contains public sector information licensed under the Open Government Licence v3.0. Traffic sign images are Crown copyright, from the Department for Transport. Sources and image credits.