Keep left sign: what it means

Keep left sign: a white vertical rectangle with a black arrow curving to the left of a black island shape
Drawing: Drivoku, based on MUTCD sign R4-8. Simplified; real signs follow the FHWA Standard Highway Signs specifications.

The Keep Left sign means you must pass only on the left-hand side of the island, median or obstacle ahead.

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What does the keep left sign mean?

MUTCD Section 2B.39 says the Keep Left sign may be used where traffic must pass only to the left-hand side of a roadway feature or obstruction. The Keep Right sign is the mirror image.

Quick quiz

What does the sign at the top of this page mean?

  1. Pass to the right of the island or obstacle.
  2. All traffic moves in the arrow’s direction.
  3. Pass to the left of the obstacle.

Show answer

C. Pass to the left of the obstacle. Traffic must pass only to the left-hand side of the obstacle (MUTCD Section 2B.39). Source: MUTCD 11th Edition, Chapter 2B, Regulatory Signs, Barricades, and Gates: Section 2B.39, FHWA; MUTCD 11th Edition, FHWA

Where will you see it?

At the ends of traffic islands and medians, usually where left-side passing is needed, such as at some channelized turns.

What should you do?

Steer to the left of the obstacle as the arrow shows. Watch for traffic and pedestrians on the island.

What do people get wrong?

Treating it as a direction to turn left. It only tells you which side of the obstacle to pass.

Common questions

Is the Keep Left sign common?

Keep Right signs are far more common, because traffic normally passes medians on the right. Keep Left is used where the layout needs it.

What is the difference from a Double Arrow sign?

The Double Arrow warning sign says you may pass on either side. Keep Left says you must pass on the left.

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Sources

Checked on 3 November 2026 against the MUTCD 11th Edition (FHWA), Section 2B.39.

  1. MUTCD 11th Edition, Chapter 2B, Regulatory Signs, Barricades, and Gates: Section 2B.39, FHWA
  2. 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.

This text was written with AI help, checked against the MUTCD and approved by Fri Vei AS. Last updated .

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