W20-5 Lane Closed Ahead Sign
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.
| 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 |
What This Sign Means
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.
California Temporary Traffic Control Use
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 TCP Context
- 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
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
- Merge direction on the sign does not match the open lane in the field.
- Taper begins before the lane-closure warning is reached.
- Sign spacing not adjusted for the posted speed.
- Wrong size specified for a multilane facility.
Plan Review Notes
Confirm the closed lane, merge direction, and taper length are consistent across the warning sequence. Public Ready reviews lane-closure tapers against speed.
Signs Commonly Used Together
These signs are typically deployed alongside W20-5 on a California TCP.
Rent or Purchase This Sign
Closing a lane on a California roadway? Public Ready can provide the LANE CLOSED AHEAD (W20-5) series and channelizing devices.
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
Need signs for a California project?
Need to rent, purchase, or include traffic control signs on a California project? Public Ready can help with sign rental, purchase, sign packages, TCP sign legends, and permit coordination.