W3-4 Be Prepared To Stop Sign
Warns drivers that they may have to stop ahead, giving advance notice of a flagging station, queue, or signal that can require stopping.
| Sign code | W3-4 |
|---|---|
| Federal code | W3-4 |
| Name | Be Prepared To Stop |
| Category | Warning Signs |
| Shape | Diamond |
| Color | Orange background, black legend (temporary traffic control use) |
| 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 drivers that they may have to stop ahead, giving advance notice of a flagging station, queue, or signal that can require stopping.
California Temporary Traffic Control Use
In California work zones the orange (temporary) version follows the Flagger sign or precedes a temporary signal, alerting drivers before they reach a stopping point.
Common TCP Context
- Ahead of flagging stations and one-lane control
- Ahead of temporary traffic signals and queues
- Paired with W20-7 Flagger in the warning sequence
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 the sign precedes the stopping point with adequate distance for the posted speed. Public Ready reviews stopping-condition warning placement.
Signs Commonly Used Together
These signs are typically deployed alongside W3-4 on a California TCP.
Rent or Purchase This Sign
Need BE PREPARED TO STOP (W3-4) for a flagging or signal setup? Public Ready can supply it with the supporting signs.
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
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