Maximum width
Official name: Closed to vehicles wider than indicated (including load)
Prohibition
Written by Chris Prosman Reviewed by Dirk van Zuijlen
Updated
- Sign code
- C18
- Category
- Prohibition
- Traffic signs
- Closed to vehicles wider than 2.3 metres.
C18 closes the road to vehicles wider than the number shown, including their load. The value is in metres. It concerns the width of the vehicle and its load, not simply the road space occupied by the tyres.
What to do at this sign
Check dimensions before reaching the restricted passage. Consider a wide load, cycle carrier or trailer. If you are uncertain of the overall width, find a safe place to establish it rather than testing the clearance while driving.
Example on the road
A trailer is 2.00 metres wide, but its load projects on both sides. At C18 showing 2.10 metres, assess the width including that load. The width of the trailer alone is not an adequate check.
Other conditions to check
C18 is a closure, not advice on a comfortable driving line. Bends, obstacles and other vehicles may make the physical passage tighter. Even below the stated limit, you must be able to pass safely.
How to recognise the sign
A circular red-bordered sign; read its symbol, text or number for the precise restriction.
Difference from C19 — Maximum height
C18 limits width; C19 limits height. Check the symbol and arrow orientation, not just the number.
C19 — Maximum heightLegal basis
Frequently asked questions
- Does C18 include the load?
- Yes. Its official definition includes width with the load.
- Is the measurement advisory?
- No. Above the stated width, the road is closed to your vehicle.
Explained in the course
Practise this sign for your theory exam
Maximum width belongs to the Prohibition category. In the CBR theory exam a traffic sign is almost never asked on its own: you are shown a situation and have to know what you may or must do in it. In the free sign trainer you practise the signs by category, with the explanation shown right after every answer.
Practise traffic signs for free Practise car theory: free mock exam
