Low Clearance Sign — Meaning

By DMV Master Editorial Team Updated April 28, 2026 Also: Bridge Clearance, Low Bridge

Category: Warning
Shape: Diamond
Colors: Yellow, Black
Text: [height] CLEARANCE
MUTCD Code: W12-2

What does the Low Clearance Sign mean?

The Low Clearance sign is a yellow diamond displaying the maximum vehicle height that can safely pass under a bridge or overhead structure. Trucks, RVs, and vehicles with rooftop loads must verify their height does not exceed the posted clearance.

What to do when you see this sign

1
Know your vehicle's exact height (including roof racks, antennas, loads)
2
If your vehicle approaches or exceeds the posted height, take an alternate route
3
Add a safety margin — actual clearance can be 3–6 inches less than posted
4
After heavy snow or ice accumulation, clearance may be reduced

Where you'll see it

At every bridge with less than 14'9" clearance (federal standard)
At parking garage entrances
Through tunnels
At railroad bridges (often the lowest)

Test trap: don't get caught by this

Most US passenger vehicles are 5–6 feet tall — well under any low-clearance sign. But RVs (10–12 ft), commercial trucks (13.5 ft typical), and vehicles with bicycles or kayaks on top can exceed clearance. Hundreds of "bridge strikes" occur each year, often due to driver inattention.

Practice questions about the Low Clearance Sign

Test your knowledge with real DMV-style questions, each with the correct answer and explanation.

What does a LOW CLEARANCE sign indicate?

View answer & explanation

What does a LOW CLEARANCE sign indicate?

View answer & explanation

What does a LOW CLEARANCE sign indicate?

View answer & explanation

States that test this sign

The Low Clearance Sign appears in DMV practice tests for 50 states. Click any state to see its full DMV practice page.

Frequently asked questions

How do I know my vehicle's height?

Check the manufacturer specs (in your owner's manual or on a label inside the door frame). For modified vehicles or loads, measure with a tape measure from ground to highest point.

Why is the actual clearance less than posted?

Snow accumulation, road repaving, and minor settling reduce real clearance. DOTs add a safety margin (typically 3 inches), but during winter or after pavement work, the margin may be eliminated.

What happens if I hit a low bridge?

Vehicle damage (potentially totaling), bridge damage (you may be liable for repair costs in the tens of thousands), criminal charges if injuries result, and impact to traffic for hours. Avoid at all costs.