Ramp Meter Ahead Sign
MUTCD W3-7
A ramp meter — a signal that releases vehicles onto the freeway one at a time — is ahead; be ready to stop and go on the entrance ramp.
What it looks like
A yellow diamond warning sign with a black legend indicating a ramp meter — a signal controlling how vehicles enter the freeway — ahead.
When you'll see it
You see it on freeway entrance ramps in busier areas where a metered signal releases vehicles onto the freeway one at a time.
What to do
Be ready to stop at the ramp signal and then proceed onto the freeway when the light turns green, one vehicle per green.
Related signs
Source: Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition — FHWA.