Single file traffic plate: what it means
Traffic goes in single file in each direction ahead. The plate is used with a road narrows warning sign.
What does the single file traffic plate mean?
Traffic goes in single file in each direction ahead. Know your traffic signs places this plate with road narrows signs.
It describes one line of traffic in each direction. Rule 167 says not to overtake where you might come into conflict with other road users, including where the road narrows.
Quick quiz
What does the sign at the top of this page mean?
- All traffic goes in the direction of the arrow.
- You go first through the narrow part, with care.
- Traffic goes in single file in each direction ahead.
Show answer
C. Traffic goes in single file in each direction ahead. The plate warns of single-file traffic in each direction (Know your traffic signs). Source: Know your traffic signs: warning signs, GOV.UK; The Highway Code, rule 167, GOV.UK; Traffic sign images, Department for Transport, GOV.UK
Where will you see it?
With a road narrows warning sign, before traffic goes into single file in each direction.
What should you do?
Proceed in single file. Do not overtake where the narrowing could bring you into conflict with other road users.
What do people get wrong?
Do not read this as one shared line for both directions. It means single-file traffic in each direction.
Common questions
Does Single file traffic mean one-way traffic?
No. Know your traffic signs says it means single-file traffic in each direction.
Which warning sign is used with Single file traffic?
Know your traffic signs lists it as a plate used with road narrows signs.
Compare with
Road narrows signThe road gets narrower ahead.
Single track road signA narrow road with passing places ahead.
Want to test someone else? Play a road-sign quiz with friends and family.
Sources
Checked on 5 November 2026 against Know your traffic signs (warning signs) and The Highway Code rule 167.
- Know your traffic signs: warning signs, GOV.UK
- The Highway Code, rule 167, 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.