Information sign
Dual carriageway ahead sign
What does the Dual carriageway ahead sign mean?
Tells you that a dual carriageway begins ahead. Keep left unless you are overtaking or turning right.
What it means
A section of dual carriageway road begins ahead.
On a dual carriageway, a central reservation separates the two directions of traffic.
Stay in the left-hand lane and use the right-hand lane only for overtaking or turning right, then move back.
Where you'll see it
Before the start of a dual carriageway. Other versions show the distance to it, or how long it lasts.
Rules to know
The sign shows that a section of dual carriageway road begins directly ahead. Other versions give the distance to it or show that it is a short length.
Know Your Traffic Signs, p. 134
On a two-lane dual carriageway you should stay in the left-hand lane. Use the right-hand lane for overtaking or turning right.
The Highway Code, Rule 137
Common mistakes
Mistake: Staying in the right-hand lane after overtaking.
Instead: Move back to the left-hand lane when it is safe.
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© Crown copyright. Free to reuse under the Open Government Licence v3.0, as long as the sign is reproduced accurately and not in a misleading context.
Related signs
Opposite
Dual carriageway ends
Warning sign
A warning that the dual carriageway ends.
More information signs
All information signs
Sources
- Know Your Traffic Signs (Department for Transport, Sixth edition, 2023), Information signs, p. 134
- The Highway Code, Rule 137
Sign image: Department for Transport, Traffic sign images (diagram 818). © Crown copyright, reused under the Open Government Licence v3.0.
Last reviewed 6 October 2026. This page explains the sign in our own words; for the full rules, see The Highway Code. How we source and check content