R9-23b BICYCLE LEFT TURN MUST USE TURN BOX Requirements
Application notes for R9-23b BICYCLE LEFT TURN MUST USE TURN BOX. The official manual distinguishes mandatory standards, recommended guidance, and optional applications; consult the linked sources for the provisions that apply.
California Application & Variants
Mount this near-side sign at the intersection where use of the turn box is required. Use the appropriate advance R9-23 or R9-23a sign as well.
1. When BICYCLE LEFT TURN MUST USE TURN BOX Is Used
Requires the bicycle left turn to use the designated two-stage turn box.
- Pedestrian and bicycle route review
2. Placement and Application Notes
Position R9-23b near side of the intersection at the mandatory two-stage bicycle turn box..
- Place the sign where the intended road users have a clear, unobstructed view on approach.
- Use the mounting height and lateral placement specified for the sign and installation type.
- Use sign assemblies and supplemental plaques only as provided in the applicable manual and approved design.
3. Layout Sizes and Visibility Considerations
Linked-layout dimensions: 12" × 18". Check the applicable MUTCD and agency requirements for the required installation size.
- Choose size based on roadway speed, sight distance, and mounting location.
- Use the visibility and material requirements specified for this sign and installation.
4. Sign Selection Checks
- Match R9-23b to the intended regulation and actual site arrangement.
- Mount this near-side sign at the intersection where use of the turn box is required. Use the appropriate advance R9-23 or R9-23a sign as well.
- Select the size and installation using the applicable California manual provisions and responsible agency requirements.
Related Resources
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Verify R9-23b Requirements
This is an educational reference. Verify sign use, size, placement, and application against the current CA MUTCD, Caltrans sign specifications, Standard Plans, and the reviewing agency. Official source links are gathered in one place.
View official sourcesEducational 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. Reference editions: California MUTCD 2026 (effective January 18, 2026) and the Federal MUTCD 11th Edition with Revision 1.
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