R4-9a — Stay In Lane To Merge Point
Sign Specifications
| Code | R4-9a |
|---|---|
| Name | Stay In Lane To Merge Point |
| Category | Regulatory |
| Shape | Rectangle |
| Color | White / black (with red where applicable) |
| CA status | Recognized in the California MUTCD (2026) |
| MUTCD reference | § 2B.20 (MUTCD 11th Edition) |
| CA MUTCD reference | California MUTCD (2026) |
What This Sign Means
The R4-9a Stay In Lane To Merge Point sign is a white regulatory sign with a black symbol or legend. It is a regulatory sign, so road users are legally required to comply with the movement or restriction it shows.
California Field Use
- Establishes the regulated movement or restriction the sign shows (stay in lane to merge point) within the temporary traffic pattern.
- Documented on the approved traffic control plan and authorized by the agency having jurisdiction.
Where It Goes on a TCP
Transition or activity area — at the point where the regulation applies.
MUTCD Requirements
The R4-9a Stay In Lane To Merge Point is addressed under Part 2 (regulatory signs) of the MUTCD 11th Edition (MUTCD § 2B.20). Read the governing standard, guidance, option, and support text in the official MUTCD before applying it.
California Requirements
California adopts this sign through the California MUTCD, sometimes with state-specific sizing or application notes. A common conventional-road size is 24 x 24 in; larger sizes apply on expressways and freeways. Confirm the size and application for your facility against the current CA MUTCD (2026) and the Caltrans sign specifications and Standard Plans.
| Application | Standard Size |
|---|---|
| Conventional Road | 24 x 24 in |
| Oversized | 30 x 30 in |
| Minimum | 18 x 18 in |
Common Plan Review Comments
- Regulatory sign not documented on the approved traffic control plan.
- Temporary regulation not authorized by the agency having jurisdiction.
- Sign size too small for the road type or speed.
Compliance Notes
- Regulation matches the approved plan.
- Sign size suits the road type and speed.
Related Signs
Related Compliance Topics
Learn more in Temporary Traffic Control.
This is an educational reference only. Always verify sign selection, size, placement, and application against the current CA MUTCD 2026, Caltrans sign specifications, Standard Plans, project documents, and the reviewing agency's requirements.