W21-5a Shoulder Closed
Warns that the shoulder is closed ahead and is not available for stopping, disabled vehicles, or travel through the work area.
- Sign Name
- Shoulder Closed
- General Meaning
- Warns that the shoulder is closed ahead and is not available for stopping, disabled vehicles, or travel through the work area.
- MUTCD Code
- W21-5a
- Typical Use
- Approach to the activity area.
- Sign Category
- Warning Signs
Specifications
- Standard Shape
- Diamond
- Background Color
- Orange
- Legend / Symbol
- Black legend
- Border
- Black
- Reflectivity
- High Intensity (for nighttime visibility)
- Compliance
- MUTCD / CA MUTCD
Standard Sizes (inches)
- 30 in Diamond30" × 30"
- 36 in Diamond36" × 36"
- 48 in Diamond48" × 48"
- 60 in Diamond60" × 60"
Material / Application Notes
Shoulder closures for staging, storage, or work space. Confirm placement and supplemental plaques against the applicable CA MUTCD standard.
View this sign on the Federal MUTCD (FHWA)California Notes
California-specific application notes and adoptions may differ. Review California requirements where applicable.
What It Means / When This Sign Is Used
In the field, W21-5a Shoulder Closed is typically positioned at the approach to the activity area. Common deployments include shoulder closures for staging, storage, or work space; used with channelizing devices closing the shoulder; common on freeway and expressway shoulder operations. Always confirm its size, retroreflective sheeting, spacing, and placement against the CA MUTCD 2026 and the reviewing agency before finalizing the traffic control plan.
Learn more about Shoulder Closed sign requirementsWhen & Where It's Used
- Shoulder closures for staging, storage, or work space
- Used with channelizing devices closing the shoulder
- Common on freeway and expressway shoulder operations
Placement on a Traffic Control Plan
- Where it sits
- Approach to the activity area.
- CA MUTCD reference
- CA MUTCD Part 6 (Temporary Traffic Control), Chapter 6F; warning-sign design in Part 2C
- Typical minimum size
- 48" × 48" on conventional roads; 60" × 60" on expressways and freeways
California / Field Use Notes
Used in California TTC zones where the shoulder is occupied by work or devices and must be taken out of service for the length of the operation.
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.
Verify the shoulder closure is clearly delineated and that emergency stopping needs are considered. Public Ready reviews shoulder-closure signing.
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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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