MUTCD W9-4: Lanes Merge Signs
The W9-4 sign is covered in Section 2C.48 of the Manual on Uniform Traffic Control Devices, 11th Edition. Below are the provisions from that section that describe when the sign is used and how it is placed.
What it means and when it is used
- Guidance · Recommended (should)The Single-Lane Transition (W4-8) sign should be located at the advance placement distance in accordance with Table 2C-3.
- Option · Permitted (may)The Lanes Merge (W9-4) sign may be used in advance of the W4-8 sign to provide additional warning that both lanes form a single lane and that a merging maneuver is needed for the traffic in each lane.Figure 2C-13. Example Sequences for Lane Ends and Lane Merge Signs (Sheet 3 of 5) W4-2L W9-1L (optional)C – Left lane on an undivided roadway - lane endsD – Left lane on a divided or one-way roadway - lane ends Legend…
Where to read the rest
- Full text: MUTCD Section 2C.48: Lanes Merge Signs
- Minimum sign sizes by roadway type are in the size section for this chapter: Section 2C.03
- Mounting height, lateral offset and retroreflectivity for any sign: MUTCD sign placement guide
Related signs in Section 2C.48
Source: Manual on Uniform Traffic Control Devices, 11th Edition (Federal Highway Administration, December 2023, public domain). Excerpts are shortened and shown out of context; read the full section before specifying a sign. Your state may still be operating under the 2009 edition or a state supplement. Official manual: mutcd.fhwa.dot.gov.