Ahead only sign: what it means
The ahead only sign means you must go straight on. Turning left or right is not allowed for traffic passing it.
What does the ahead only sign mean?
A blue circle generally gives a positive instruction: something you must do (Know your traffic signs). This one tells you to proceed in the direction of the arrow, and The Highway Code names it ahead only.
Rule 109 says you must obey signs that give orders.
Quick quiz
What does the sign at the top of this page mean?
- Go straight ahead only.
- Pass on the left of the island or bollard.
- You must turn left at the junction ahead.
Show answer
A. Go straight ahead only. The upward arrow means you must go straight ahead (The Highway Code). Source: Know your traffic signs: regulatory signs, GOV.UK; The Highway Code, rule 109, GOV.UK; The Highway Code: traffic signs, GOV.UK
Where will you see it?
At junctions and on approaches where traffic must carry straight on instead of turning.
What should you do?
Carry straight on. If you meant to turn, take the next legal turning and find another way round.
What do people get wrong?
Mixing it up with the one-way traffic sign. The round ahead only sign is an order to go straight on; the rectangular one-way sign tells you which way traffic flows.
Common questions
What does a blue circle with a white arrow pointing up mean?
It means ahead only. You must go straight ahead (The Highway Code).
Is the ahead only sign an instruction or advice?
It is an instruction. Rule 109 says you must obey traffic signs that give orders.
Compare with
One-way traffic signAll traffic goes in the direction of the arrow.
Turn left ahead signYou must turn left at the junction 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 (regulatory signs) and The Highway Code (rule 109; traffic signs).
- Know your traffic signs: regulatory signs, GOV.UK
- The Highway Code, rule 109, GOV.UK
- The Highway Code: traffic signs, 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.