Low Clearance sign
An overpass or other overhead structure ahead has a vertical clearance lower than 14 feet 6 inches (or less than 12 inches above the legal maximum vehicle height); the sign shows the clearance.
What to do
If your vehicle (including any load) is taller than the height shown, do not go under it; take another route.
Know your vehicle's height including any roof load or trailer, and if it is at or above the posted figure, turn off at the last detour point before the structure.
Where it's used
Section 2C.25 requires the Low Clearance (W12-2) sign before any overhead structure with a clearance under 14 feet 6 inches, or under 12 inches above the legal maximum vehicle height if that is greater. It is a black-on-yellow diamond with arrows above and below the clearance figure, shown to the nearest inch without exceeding the real clearance (up to 3 inches less in frost areas). It should also be posted with a distance plaque at the last place to detour or turn around, and Low Clearance Overhead (W12-2a, W12-2b) signs may be mounted on the structure itself.
Don't confuse it with
- Weight Limit: The Weight Limit sign restricts heavy vehicles, while Low Clearance warns tall vehicles about height.
- Narrow Bridge: NARROW BRIDGE warns about width, not height.
- Type
- Warning signs
- Shape
- Diamond
- Colors
- yellow, black
- MUTCD code
- W12-2
- MUTCD section
- 2C.25
On state permit tests
Our questions for 10 states ask about this sign, including Florida, Georgia, Indiana, Michigan and Montana.
Test yourself
A LOW CLEARANCE sign tells you: (Florida practice test)
- Do not enter if your vehicle is taller than the height shown
- The road narrows ahead
- The speed limit for tall vehicles
- Trucks must use the left lane
Show answer
Do not enter if your vehicle is taller than the height shown. Do not enter if your vehicle is taller than the height listed on the sign.
What does a 'Low Clearance' sign warn you about? (Georgia practice test)
- A low bridge or underpass; do not enter if your vehicle or cargo is taller than shown
- A dip in the road
- Low speed limit
- Low shoulder
Show answer
A low bridge or underpass; do not enter if your vehicle or cargo is taller than shown. Approaching a low underpass; do not enter if your vehicle or cargo exceeds the height shown.
More warning signs
Turn
Curve
Reverse Turn
Reverse Curve
Winding Road
One-Direction Large Arrow
Two-Direction Large Arrow
Chevron AlignmentFrom the Manual on Uniform Traffic Control Devices (MUTCD), 11th edition, section 2C.25. Sign image: public domain, source.