MUTCD R4-21: ALL TRAFFIC Sign and RIGHT TURN ONLY Sign
The R4-21 sign is covered in Section 2B.44 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
- Option · Permitted (may)The ALL TRAFFIC (R4-20) sign may be used at an intersection where all traffic on the approach to the intersection must turn in the direction indicated and the Movement Prohibition (see Section 2B.26) and/or ONE WAY (see Section 2B.49) signs do not adequately convey the allowable direction of travel.
- Option · Permitted (may)The RIGHT (LEFT) TURN ONLY (R4-21) sign may be used at or on an approach to an intersection where all traffic on that approach must turn in the direction indicated.
Where to read the rest
- Full text: MUTCD Section 2B.44: ALL TRAFFIC Sign and RIGHT TURN ONLY Sign
- Minimum sign sizes by roadway type are in the size section for this chapter: Section 2B.03
- Mounting height, lateral offset and retroreflectivity for any sign: MUTCD sign placement guide
Related signs in Section 2B.44
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.