Curve Sign
MUTCD W1-2
The road curves ahead; reduce speed.
What it looks like
A yellow diamond warning sign with a black arrow curving gradually to indicate a bend in the road ahead.
When you'll see it
You meet it before a gentle curve on highways and connector roads, often with an advisory speed plaque showing a safe speed.
What to do
Reduce your speed as you approach and adjust steering to follow the curve without drifting out of your lane.
Related signs
Source: Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition — FHWA.