What does the Low Clearance sign mean?
The Low Clearance sign (MUTCD W12-2) is a warning sign under the federal Manual on Uniform Traffic Control Devices, the national standard the states build from. The structure ahead has less headroom than the posted figure.
Source: MUTCD 11th Edition, Chapter 2C, Table 2C-1, checked 2026-09-09.
What shape and color is the Low Clearance sign?
| MUTCD code | W12-2 |
|---|---|
| Group | Warning signs |
| Shape | Diamond (advance) or horizontal rectangle (mounted on the structure) |
| Color | Yellow background, black legend and border |
What a diamond means. A warning. It tells you what the road does next and obliges you to do nothing in particular, which is the distinction test writers probe most often.
What yellow means. General warning of a permanent condition ahead.
Warning signs. A diamond reports a condition and orders nothing. What you do about it is left to you, and that gap between a report and an order is what test writers keep probing.
What is the Low Clearance sign often mistaken for?
Weight Limit signs (R12 series). Clearance is a height restriction and comes up often on the CDL test; the driver, not the sign, is responsible for knowing vehicle height.
|  |
|---|---|
| GroupWarning signs | GroupRegulatory signs |
| ShapeDiamond (advance) or horizontal rectangle (mounted on the structure) | ShapeVertical rectangle |
| ColorYellow background, black legend and border | ColorWhite background, black legend and border |
| What it meansThe structure ahead has less headroom than the posted figure. | What it meansThe structure or the surface beneath it cannot carry more than the posted gross figure, so a heavier vehicle has to be routed around it. |
Which signs get mistaken for the Low Clearance sign?
Low Ground Clearance Grade CrossingW10-5Low Clearance (W12-2), which is about height above the vehicle. W10-5 is about the underside of the vehicle grounding out, and it is a CDL question.
What are the other warning signs?
All 55 warning signs on one page, or every US road sign by shape and color.
Test yourself on this sign and the rest of the set with a road signs practice test for Florida, Texas or California.
The artwork is the federal design itself, which the manual dedicates to the public domain in MUTCD 11th Edition, Part 1, Section 1D.06, checked 2026-09-09. The Interstate Shield, the 511 pictograph and the National Scenic Byway graphic are named exceptions and are not reproduced anywhere on this site.
Source: Manual on Uniform Traffic Control Devices, 11th Edition. Not affiliated with or endorsed by the Federal Highway Administration or any state agency.