What it looks like
A yellow diamond warning sign with a black symbol indicating a bridge wide enough for only one vehicle at a time.
When you'll see it
It appears before a single-lane bridge on narrow rural roads where only one direction of traffic can cross at once.
What to do
Slow down and yield to any vehicle already on or first to reach the bridge; cross only when the way is clear.
Source: Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition — FHWA.
