what does this symbol mean?
MUTCD W3-3 A yellow diamond with a traffic signal showing red, yellow and green

Signal ahead sign

A yellow diamond with a traffic signal. It warns of traffic lights ahead that are not yet in view.

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 requires it on an approach where the signal cannot be seen from far enough away for drivers to respond, judged by a continuous view of at least two signal faces. The view may be blocked by the road's alignment or a structure, or at times by foliage or parked vehicles, and Pennsylvania's manual names a curve or a hill.

More road signs

Sources

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

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