Advisory Speed Sign
MUTCD W13-1P
The safe speed for the condition ahead is the speed shown.
What it looks like
A square yellow plaque with black speed numerals, mounted directly below a warning sign.
When you'll see it
Below curve, ramp, or other warning signs where the road condition calls for a lower speed than the regular posted limit.
What to do
Reduce your speed to the shown advisory speed for the condition ahead; it is the safe speed to travel that section.
Related signs
Source: Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition — FHWA.