Low Clearance Sign

Updated July 9, 2026

Low Clearance · MUTCD W12-2 · Warning sign

What the Low Clearance sign means

This yellow sign posts the height of an overpass, bridge, or tunnel ahead, warning that clearance is limited. The number tells you the maximum vehicle height that can safely pass under. If your vehicle, with any load, is taller, do not proceed — find an alternate route. It is posted before low structures to prevent trucks, RVs, and loaded vehicles from striking them. Most car drivers can ignore it, but anyone driving something tall must compare their height to the posted figure before continuing.

What to do when you see it

Compare your vehicle’s height to the posted clearance; if you are taller, take a different route — do not risk it.

On the CA permit test

Low Clearance posts the maximum height that fits under the structure ahead.

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