What it looks like
A yellow diamond-shaped warning sign showing the black maximum clearance height, marking limited overhead clearance ahead.
When you'll see it
Ahead of low bridges, overpasses, tunnels, and other overhead structures where tall vehicles may not fit.
What to do
Tall vehicles must not proceed if they exceed the posted clearance; know your vehicle's height and find an alternate route if it is too tall.
Source: Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition — FHWA.
