W1-4c Reverse Curve (3 lanes)
Warns of a three-lane reverse-curve alignment ahead — a curve in one direction followed by a curve in the other — such as a multilane lane shift around a work area.
- Sign Name
- Reverse Curve (3 lanes)
- General Meaning
- Warns of a three-lane reverse-curve alignment ahead — a curve in one direction followed by a curve in the other — such as a multilane lane shift around a work area.
- MUTCD Code
- W1-4c
- Typical Use
- Advance warning area, ahead of the work.
- 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
Three-lane lane shifts around work activity. 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, W1-4c Reverse Curve (3 lanes) is typically positioned at the advance warning area, ahead of the work. Common deployments include three-lane lane shifts around work activity; multilane temporary alignment changes / crossovers; used with channelizing devices through the shift. 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 Reverse Curve (3 lanes) sign requirementsWhen & Where It's Used
- Three-lane lane shifts around work activity
- Multilane temporary alignment changes / crossovers
- Used with channelizing devices through the shift
Placement on a Traffic Control Plan
- 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
- Typical minimum size
- 48" × 48" on conventional roads; 60" × 60" on expressways and freeways
California / Field Use Notes
Used where a California work zone shifts three lanes of traffic through a reverse (S) alignment, for example around a median rebuild or a temporary crossover.
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.
Confirm the reverse-curve advisory and any advisory-speed plaque match the geometry of the multilane shift. Public Ready reviews lane-shift 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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