Sign library · Warning

SIGNAL AHEAD

ColorYellow
ShapeDiamond
FamilyWarning
Where you see itBefore intersections hidden by hills, curves, or speed

What it means

A traffic light is coming that you cannot see yet, or cannot see in time. Posted where drivers arriving at speed would meet a red light with no warning.

What you should do

Ease off and arrive ready to stop. If the light has been green a long while as you approach, expect it to change.

Memory trick

A picture of a traffic light before the traffic light. The road is whispering "red is possible ahead."

The mistake drivers make

Speeding up to catch the green. The sign exists precisely because you cannot judge that light from here.

Test yourself on this sign.

A real practice question from our verified bank, word for word. Tap an answer.

Q.A yellow diamond-shaped sign is used to:

Related signs

Signs that live in the same family, or get confused with this one.

STOP AHEAD

Yellow · Diamond

CURVE AHEAD

Yellow · Diamond

Keep going.

The library

Every sign, one page each

Browse the full sign library: meanings, memory tricks, and the mistakes to avoid.

Back to the library →
The system

The color and shape codes

One lesson that teaches you to read any sign from its outline alone.

Learn the codes →
All topics

Explore the Learning Center

Six free lessons that cover the whole written test.

See all lessons →

Prefer to study on your phone, in your own language? The same questions live in the app — 19 languages, all 50 states, every answer explained.