Warns that a travel lane is closed ahead and that drivers in that lane will need to merge into an adjacent open lane before the work area.
MUTCD-style sign reference illustration. Always verify against the official CA MUTCD and Caltrans sign charts.
| Sign code | W20-5 |
|---|---|
| Federal code | W20-5 |
| Name | Lane Closed 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 |
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 that a travel lane is closed ahead and that drivers in that lane will need to merge into an adjacent open lane before the work area.
Warns that a travel lane is closed ahead and that drivers in that lane will need to merge into an adjacent open lane before the work area. In the field, W20-5 Lane Closed Ahead is typically positioned at the advance warning area, ahead of the work. Common deployments include multilane lane-closure setups on streets and highways; used ahead of the merging taper and channelizing devices; paired with W4-2 Lane Ends / Merge symbol signs. Always confirm its size, retroreflective sheeting, spacing, and placement against the CA MUTCD 2026 and the reviewing agency before finalizing the traffic control plan.
Base lane-closure warning used in California multilane TTC setups; the directional variants (W20-5a/W20-5b) call out which lane closes ahead of the taper.
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 closed lane, merge direction, and taper length are consistent across the warning sequence. Public Ready reviews lane-closure tapers against speed.
These signs are typically deployed alongside W20-5 on a California TCP.
Closing a lane on a California roadway? Public Ready can provide the LANE CLOSED AHEAD (W20-5) series and channelizing devices.
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 W20-5 Lane Closed Ahead, visit WorkZoneCompliance.com.
Public Ready can help with W20-5 Lane Closed Ahead — 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.
