What does the Type 3 Object Marker mean?
The Type 3 Object Marker (MUTCD OM3-L, OM3-R) is a warning sign under the federal Manual on Uniform Traffic Control Devices, the national standard the states build from. It marks an obstruction close to or in the roadway; the stripes slope down toward the side you should pass on.
Source: MUTCD 11th Edition, Chapter 2C, Table 2C-1, checked 2026-09-09.
What shape and color is the Type 3 Object Marker?
| MUTCD code | OM3-L, OM3-R |
|---|---|
| Group | Warning signs |
| Shape | Vertical rectangle, 12 by 36 inches |
| Color | Alternating black and retroreflective yellow stripes at 45 degrees |
What a vertical rectangle means. Usually regulatory: a law you must obey. Speed limits, turn restrictions and parking rules take this shape. Rectangles are the loosely assigned outline in the system, though, so on this sign the shape alone does not tell you its family; the color and the legend do.
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 Type 3 Object Marker often mistaken for?
Being read as decoration. The direction of the stripe slope is the instruction, and the left and right versions are mirror images.
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.