Left turn only sign: what it means
The LEFT ONLY lane sign means the lane under it must turn left. If you are in that lane, you must turn left at the intersection.
What does the left turn only sign mean?
MUTCD Section 2B.28 says Mandatory Movement Lane Control signs show the single movement required from the lane, include the word ONLY and are mounted overhead over the lane they apply to. A post-mounted version reads LEFT LANE MUST TURN LEFT.
Quick quiz
What does the sign at the top of this page mean?
- Do not turn left here.
- A center lane for left turns from both directions.
- This lane must turn left.
Show answer
C. This lane must turn left. Mandatory Movement Lane Control signs show the single movement required from that lane (MUTCD Section 2B.28). Source: MUTCD 11th Edition, Chapter 2B, Regulatory Signs, Barricades, and Gates: Sections 2B.27, 2B.28, FHWA; MUTCD 11th Edition, FHWA
Where will you see it?
Over the lanes on the approach to an intersection, usually together with white turn arrows painted in the lane.
What should you do?
Read the overhead signs early and get into the lane for the way you want to go. If you end up in a turn-only lane by mistake, make the turn and find your way back.
What do people get wrong?
Driving straight on from a left-only lane at the last moment. That cuts across traffic that is turning with you.
Common questions
Does the sign apply to the lane next to it?
No. MUTCD Section 2B.28 says these signs are mounted over the specific lanes they apply to.
What if I am in the wrong lane?
Follow the lane’s required movement, then find a safe and legal way back to your route.
Compare with
No left turn signDo not turn left here.
Two-way left-turn laneA center lane for left turns from both directions.
Want to test someone else? Play a road-sign quiz with friends and family.
Sources
Checked on 3 November 2026 against the MUTCD 11th Edition (FHWA), Sections 2B.27 and 2B.28.
- MUTCD 11th Edition, Chapter 2B, Regulatory Signs, Barricades, and Gates: Sections 2B.27, 2B.28, FHWA
- MUTCD 11th Edition, FHWA. FHWA lists the current version as the 11th Edition with Revision 1, dated December 2025
Sign pictures are our own simplified drawings of the MUTCD designs, which are in the public domain (MUTCD Section 1D.06). Sources and image credits.