OM1-3 OBJECT MARKER (TYPE 1) Requirements
Application notes for OM1-3 OBJECT MARKER (TYPE 1). The official manual distinguishes mandatory standards, recommended guidance, and optional applications; consult the linked sources for the provisions that apply.
1. When OBJECT MARKER (TYPE 1) Is Used
A Type 1 object marker with a solid yellow diamond-shaped face. It identifies an obstruction within or adjacent to the roadway; it has no directional stripes.
- Marking obstructions near the traveled way
- Delineating equipment and fixed hazards
- Supplementing channelizing devices
2. Placement and Application Notes
Position OM1-3 at the obstruction being marked, per CA MUTCD Chapter 2C.
- Place the sign where the intended road users have a clear, unobstructed view on approach.
- Use the mounting height and lateral placement specified for the sign and installation type.
- Use sign assemblies and supplemental plaques only as provided in the applicable manual and approved design.
3. Layout Sizes and Visibility Considerations
Linked-layout dimensions: 18" × 18". Check the applicable MUTCD and agency requirements for the required installation size.
- Choose size based on roadway speed, sight distance, and mounting location.
- Use the visibility and material requirements specified for this sign and installation.
4. Sign Selection Checks
- Match OM1-3 and its displayed legend to the intended condition.
- Check the source drawing for the required directional or message variant.
- Select the marker type and, for striped markers, the side on which traffic passes.
Related Resources
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Verify OM1-3 Requirements
This is an educational reference. Verify sign use, size, placement, and application against the current CA MUTCD, Caltrans sign specifications, Standard Plans, and the reviewing agency. Official source links are gathered in one place.
View official sourcesEducational reference only. This is not an official Caltrans, FHWA, or local agency publication and is not legal or engineering advice. Always verify sign selection, size, placement, spacing, and application against the current CA MUTCD 2026, Caltrans sign specifications, Standard Plans, project documents, and the reviewing agency’s requirements. Local jurisdictions may impose additional requirements, and final selection, placement, and dimensions may require engineering judgment or agency approval. Reference editions: California MUTCD 2026 (effective January 18, 2026) and the Federal MUTCD 11th Edition with Revision 1.
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