Warns drivers that they may have to stop ahead, giving advance notice of a flagging station, queue, or signal that can require stopping.
MUTCD-style sign reference illustration. Always verify against the official CA MUTCD and Caltrans sign charts.
| 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 |
Download this sign or open the official MUTCD reference.
Official source: FHWA Standard Highway Signs, 2024 (11th Edition) — Warning & Temporary Traffic Control signs.
Source: FHWA Standard Highway Signs — Public Domain. California: CA MUTCD 2026 (effective Jan 18, 2026).
Files linked from FHWA are official government publications in the public domain. CA MUTCD and Caltrans links open official government websites. Always verify against the current edition.
Warns drivers that they may have to stop ahead, giving advance notice of a flagging station, queue, or signal that can require stopping.
Warns drivers that they may have to stop ahead, giving advance notice of a flagging station, queue, or signal that can require stopping. In the field, W3-4 Be Prepared To Stop is typically positioned at the advance warning area, ahead of the work. Common deployments include ahead of flagging stations and one-lane control; ahead of temporary traffic signals and queues; paired with W20-7 Flagger in the warning sequence. Always confirm its size, retroreflective sheeting, spacing, and placement against the CA MUTCD 2026 and the reviewing agency before finalizing the traffic control plan.
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 field deployments
Agency review note
StreetsLA, LA County DPW, and Caltrans District 7 may require larger sizes or additional devices. Verify with the reviewing agency before finalizing the TCP.
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.
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.
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.
Confirm the sign precedes the stopping point with adequate distance for the posted speed. Public Ready reviews stopping-condition warning placement.
These signs are typically deployed alongside W3-4 on a California TCP.
Need BE PREPARED TO STOP (W3-4) for a flagging or signal setup? Public Ready can supply it with the supporting signs.
Free official resource — opens official government website
Free official resource — opens official government website
Free official resource — opens official government website
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.
To understand the bigger picture around permits, agency review, lane closures, and pedestrian access for work zones using W3-4 Be Prepared To Stop, visit WorkZoneCompliance.com.
Public Ready can help with W3-4 Be Prepared To Stop — including sign rental or purchase, work-zone signs, TCP sign legends, and permit coordination, and agency-review support for Caltrans District 7, the City of Los Angeles, and LA County.
