ROAD WORK AHEAD Sign Requirements
This guide summarizes the MUTCD requirements and practical application guidance for the C23(CA) ROAD WORK AHEAD 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
Applied per the CA MUTCD and Caltrans sign specifications
Where It Applies
Advance warning area, ahead of the work.
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 ROAD WORK AHEAD Sign Is Used
The C23(CA) Road Work Ahead is a California construction sign. Verified against the official Caltrans Sign Specification (C23--CA.pdf): the sheet shows ROAD WORK AHEAD. Colors: ORANGE BACKGROUND WITH BLACK BORDER & SYMBOL (REFLECTIVE BACKGROUND). Standard sizes: 30x30, 48x48 in.
- Applied per the CA MUTCD and Caltrans sign specifications
- Selected and sized for the roadway type and setting
- Coordinated with the overall signing plan and permit
2. How and Where It Applies
In the field, C23(CA) Road Work Ahead is typically positioned at the advance warning area, ahead of the work. Common deployments include applied per the CA MUTCD and Caltrans sign specifications; selected and sized for the roadway type and setting; coordinated with the overall signing 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 C23(CA) advance warning area, ahead of the work.
- 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: 48" × 48" on conventional roads; 60" × 60" on expressways and freeways.
- Choose size based on roadway speed, sight distance, and mounting location.
- Maintain high retroreflectivity for maximum night and adverse-weather visibility.
5. California Notes
Used in California per the CA MUTCD and the Caltrans Sign Specification (C23--CA.pdf). Confirm size, retroreflective sheeting, and placement for the specific condition and the reviewing agency.
Go to California Notes6. Common Field or Planning Mistakes
- Designation verified against the Caltrans Sign Specification (C23--CA.pdf).
- Verify size for the roadway classification and setting.
- Confirm retroreflective sheeting class per the CA MUTCD.
- Verify placement and mounting height per the CA MUTCD.
Related Resources
View All C-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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