what does this symbol mean?
MUTCD W4-3 A yellow diamond with a line joining alongside another, both continuing

Added lane sign

A yellow diamond with a line joining alongside another, both carrying on. It warns that traffic from another road enters in its own new lane.

Rules vary by state and country. This explains the sign's standard meaning in the U.S. Manual on Uniform Traffic Control Devices; it isn't legal advice.

How to read it

The MUTCD uses it ahead of a point where two roads come together and no merging is needed. As Pennsylvania's manual puts it, the entering traffic uses a new lane added to the road.

Added lane or merge

Where the lanes do come together into one, the Merge sign is used instead.

More road signs

Sources

Last reviewed September 25, 2026 by Rory Hansen. How we research

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