Warning signs
Traffic Signal Ahead sign
A traffic light is coming, often where you cannot see it in time otherwise.
- Diamond
- Yellow
- MUTCD W3-3
How to recognize it
Shape and background first
ShapeDiamonda diamond stood on its point
BackgroundYellowyellow, the warning color
FamilyWarning signsFederal designation W3-3 in the MUTCD.
Federal designation W3-3 in the MUTCD, the national standard every state signs to.
What the MUTCD specifies
Designation: W3-3
MUTCD Section 2C.35
Conventional road size: 30 x 30 in
Source: Federal Highway Administration, MUTCD 11th Edition (December 2023), Part 2, Table 2C-1; Table 2C-3, Condition B, potential stop, verified 2026-09-26.
Where you will see it
Suggested advance placement distance by posted speed (MUTCD guidance, MUTCD 11th Edition (December 2023), Part 2, Table 2C-1; Table 2C-3, Condition B, potential stop, verified 2026-09-26):
- 35 mph: 250 ft
- 45 mph: 360 ft
- 55 mph: 495 ft
On the test
What the test wants you to know
The mistake people make
It is posted where a hill, curve or trees hide the signal. Treat it as an instruction to cover the brake and be ready for a stale green to change.
Same family
