OBJECT MARKER TYPE 4 Sign Requirements
This guide summarizes the MUTCD requirements and practical application guidance for the OM4-3 OBJECT MARKER TYPE 4 sign. Use this resource to understand when it is required, how to place it correctly, and how to maintain clear visibility for safe operations.
When It Is Used
Used where object marker type 4 conditions apply on a California project
Where It Applies
At (or leading up to) the obstruction it marks, per CA MUTCD object-marker standards.
Placement Basics
Mount at the standard height and setback for the roadway with clear sight lines.
Visibility / Reflectivity
High reflectivity and clear sight lines are essential day and night.
1. When a OBJECT MARKER TYPE 4 Sign Is Used
The OM4-3 Object Marker Type 4 sign is a California MUTCD object marker sign. It is shown here as an educational reference with the official FHWA Standard Highway Signs layout and California sizing guidance.
- Used where object marker type 4 conditions apply on a California project
- Selected and sized per the CA MUTCD and the roadway type
- Coordinated with the overall traffic control plan and permit
2. How and Where It Applies
In the field, OM4-3 Object Marker Type 4 is typically positioned at the at (or leading up to) the obstruction it marks, per ca mutcd object-marker standards. Common deployments include used where object marker type 4 conditions apply on a California project; selected and sized per the CA MUTCD and the roadway type; coordinated with the overall traffic control plan and permit. Always confirm its size, retroreflective sheeting, spacing, and placement against the CA MUTCD 2026 and the reviewing agency before finalizing the traffic control plan.
3. Placement and Application Notes
Position OM4-3 at (or leading up to) the obstruction it marks, per CA MUTCD object-marker standards.
- Place the sign where drivers have a clear, unobstructed view on approach.
- Mount at the standard height and setback from the edge of the traveled way.
- Do not mount with other signs on the same post unless space constraints require it.
4. Standard Sizes and Visibility Considerations
Typical minimum: Per CA MUTCD object-marker standards.
- Choose size based on roadway speed, sight distance, and mounting location.
- Maintain high retroreflectivity for maximum night and adverse-weather visibility.
5. California Notes
OM4-3 Object Marker Type 4 is used in California per the CA MUTCD. Confirm its size, retroreflective sheeting, placement, and spacing against the CA MUTCD 2026 and the reviewing agency before finalizing the traffic control plan.
Go to California Notes6. Common Field or Planning Mistakes
- Object marker omitted on a hazard that remains near traffic.
- Stripe direction does not guide traffic to the correct side.
- Marker type not appropriate for the obstruction.
- Delineation not continuous with the channelizing devices.
Related Resources
View All OM-Series Signs
Educational 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. Written against California MUTCD 2026 (effective January 18, 2026) and the Federal MUTCD 11th Edition. Official sources last verified June 2026.
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