Road narrows on one side sign: what it means
This warning triangle means the road ahead narrows on one side. The line that bends in shows which side, here the right.
What does the road narrows on one side sign mean?
Know your traffic signs describes it as “road narrows on right (left if symbol reversed)”. The road narrows on both sides sign has both lines bending in.
Quick quiz
What does the sign at the top of this page mean?
- Oncoming traffic goes first through the narrow part.
- The dual carriageway ends ahead.
- The road gets narrower on one side ahead.
Show answer
C. The road gets narrower on one side ahead. It warns that the road narrows on one side, the side the line bends in (Know your traffic signs). Source: Know your traffic signs: warning signs, GOV.UK; Know your traffic signs: traffic calming, GOV.UK; Traffic sign images, Department for Transport, GOV.UK
Where will you see it?
Before bridges, build-outs and other places where the road loses width on one side.
What should you do?
Slow down and check for oncoming traffic, cyclists and parked cars in the narrow part.
What do people get wrong?
Reading it as a lane ending on a dual carriageway. It shows the road itself getting narrower.
Common questions
How do I know which side narrows?
Look at the lines. The one that bends in is the side that narrows.
Who has priority at a narrowing?
This sign does not say. Priority signs may tell you, such as give way to oncoming vehicles.
Compare with
Road narrows signThe road gets narrower ahead.
Give way to oncoming vehicles signOncoming traffic goes first through the narrow part.
Want to test someone else? Play a road-sign quiz with friends and family.
Sources
Checked on 4 November 2026 against Know your traffic signs (warning signs; traffic calming).
- Know your traffic signs: warning signs, GOV.UK
- Know your traffic signs: traffic calming, 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.