W21-7 Utility Work Ahead Sign
Warns that utility work is taking place on or near the roadway ahead, alerting drivers to utility crews, equipment, and possible lane or shoulder impacts.
| Sign code | W21-7 |
|---|---|
| Federal code | W21-7 |
| Name | Utility Work Ahead |
| Category | Warning Signs |
| Shape | Diamond |
| Color | Orange background, black legend |
| California status | Used in California per CA MUTCD |
| Typical CA minimum size | 48" × 48" on conventional roads; 60" × 60" on expressways and freeways |
What This Sign Means
Warns that utility work is taking place on or near the roadway ahead, alerting drivers to utility crews, equipment, and possible lane or shoulder impacts.
California Temporary Traffic Control Use
Used by utilities and their contractors in California right-of-way for water, power, gas, and communications work that affects the roadway.
Common TCP Context
- Utility maintenance and installation in the right-of-way
- Short-duration and mobile utility operations
- Encroachment-permit work for utility agencies
California Size Requirements
Typical minimum: 48" × 48" on conventional roads; 60" × 60" on expressways and freeways.
Sizes are CA MUTCD minimums and vary by roadway classification and speed. Verify against the CA MUTCD 2026 (CA MUTCD Part 6 (Temporary Traffic Control), Chapter 6F; warning-sign design in Part 2C), Caltrans sign specifications, and the reviewing agency.
Common Placement on a TCP
Where it sits: Advance warning area, ahead of the work.
CA MUTCD reference: CA MUTCD Part 6 (Temporary Traffic Control), Chapter 6F; warning-sign design in Part 2C.
Los Angeles Area Usage Notes
In Los Angeles, this sign must conform to CA MUTCD 2026. Work in City of LA right-of-way is reviewed by StreetsLA and the Bureau of Engineering (BOE); state highways in LA County are permitted and reviewed by Caltrans District 7; county roads are permitted by LA County DPW. Sizes, retroreflectivity, and placement must meet CA MUTCD minimums — local agencies may require larger signs based on roadway class, speed, pedestrian volume, and proximity to schools or transit.
Common Plan Review Comments
- Sign not shown at the correct advance distance for the posted speed.
- Advance warning sign missing or out of sequence on the TCP.
- Wrong size specified for the roadway classification (conventional vs. expressway).
- Sign sheeting / retroreflectivity class not noted on the plan.
Plan Review Notes
Confirm utility-specific warning is used and that permit conditions are reflected in the TCP. Public Ready supports utility encroachment-permit signing.
Signs Commonly Used Together
These signs are typically deployed alongside W21-7 on a California TCP.
Rent or Purchase This Sign
Doing utility work in the right-of-way? Public Ready can supply UTILITY WORK AHEAD (W21-7) and the full sign package.
Official References
- California MUTCD (Caltrans)
Free official resource — opens official government website
- Federal MUTCD (FHWA)
Free official resource — opens official government website
- Caltrans Sign Charts
Free official resource — opens official government website
- FHWA Standard Highway Signs
Free official resource — opens official government website
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.
Related Signs
Need signs for a California project?
Need to rent, purchase, or include traffic control signs on a California project? Public Ready can help with sign rental, purchase, sign packages, TCP sign legends, and permit coordination.