Signal ahead sign: what it means

Signal ahead warning sign: a yellow diamond with a traffic light showing red, yellow and green
Drawing: DriveQuiz, based on MUTCD sign W3-3. Simplified; real signs follow the FHWA Standard Highway Signs specifications.

The Signal Ahead sign warns of a traffic signal ahead that may be hard to see in time. Be ready to stop.

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What it means

MUTCD Section 2C.35: the Signal Ahead sign is installed on the approach to a traffic signal that drivers cannot see from far enough away. For a signal, that means a continuous view of at least two signal faces for the distance drivers need.

It may also be used for extra emphasis even when the signal can be seen.

Where you see it

Before traffic signals around curves, over hills or where the view is blocked.

A common mistake

Speeding up to beat a light you cannot see yet. Slow down so you can stop if it turns yellow or red.

Quick quiz

What should you expect after a Signal Ahead sign?

  1. A traffic signal
  2. A STOP sign only
  3. A railroad crossing
Show answer

A. A traffic signal. The W3-3 sign warns of a traffic signal ahead. Source: MUTCD 11th Edition, Chapter 2C, Warning Signs and Object Markers: Section 2C.35, FHWA; MUTCD 11th Edition, FHWA

Compare with

Next in warning signs: Merge sign. See all warning signs or the full road signs list.

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Sources

  1. MUTCD 11th Edition, Chapter 2C, Warning Signs and Object Markers: Section 2C.35, 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.