Low clearance sign
A yellow sign giving a height between two arrows. It warns of a bridge, tunnel or other structure ahead with limited headroom.
How to read it
The MUTCD requires it where the clearance is less than 12 inches above the maximum vehicle height allowed by law. Pennsylvania's manual lists where it appears: on an underpass, or at the entrance to a tunnel or parking garage. The height on the sign is the limit for vehicles passing underneath: Michigan's example reads 12 feet 6 inches.
Rules vary by state and country. This explains the sign's standard meaning in the U.S. Manual on Uniform Traffic Control Devices; it isn't legal advice.
Why the figure can read low
The height shown is rounded down to the nearest inch below the real clearance. In places where frost action changes the clearance, the MUTCD takes up to 3 more inches off.
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The same shape elsewhere
Browse symbols drawn with arrows, diamonds or letters and numbers.
Sources
- MUTCD 2009 Edition, Chapter 2C: Warning Signs and Object Markers, MUTCD 2009, Part 2, U.S. Federal Highway Administration, Section 2C.27
- Pennsylvania Driver's Manual, Chapter 2: Signals, Signs and Pavement Markings, Pennsylvania Department of Transportation, p. 16
- What Every Driver Must Know, Michigan driver manual, Michigan Department of State, Chapter 5, sign 38
- Official Florida Driver License Handbook, rev. 08/2023, Florida Department of Highway Safety and Motor Vehicles, p. 51
Researched, edited and approved by Rory Hansen before publishing. Last reviewed September 25, 2026. How we research
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