What does the Slower Traffic Keep Right sign mean?
The Slower Traffic Keep Right sign (MUTCD R4-3) is a regulatory sign under the federal Manual on Uniform Traffic Control Devices, the national standard the states build from. Vehicles moving slower than the general flow must use the right-hand lane.
Source: MUTCD 11th Edition, Chapter 2B, Table 2B-1, checked 2026-09-09.
What shape and color is the Slower Traffic Keep Right sign?
| MUTCD code | R4-3 |
|---|---|
| Group | Regulatory signs |
| Shape | Vertical rectangle |
| Color | White background, black legend and border |
What a vertical rectangle means. Usually regulatory: a law you must obey. Speed limits, turn restrictions and parking rules take this shape.
What white means. Regulatory. A black legend on a white background is a law, not advice.
Regulatory signs. Every sign in this group has a statute behind it, so disobeying one is a citable offense on its own. Permit tests tend to word them as a duty you owe rather than show you the face.
What is the Slower Traffic Keep Right sign often mistaken for?
Keep Right (R4-7), which is about passing an obstruction, and Keep Right Except To Pass (R4-16), which is a stricter lane-discipline rule.
|  |
|---|---|
| GroupRegulatory signs | GroupRegulatory signs |
| ShapeVertical rectangle | ShapeVertical rectangle |
| ColorWhite background, black legend and border | ColorWhite background, black arrow and border |
| What it meansVehicles moving slower than the general flow must use the right-hand lane. | What it meansThe divider immediately ahead has to finish up on your left. |
What are the other regulatory signs?
All 39 regulatory signs on one page, or every US road sign by shape and color.
Test yourself on this sign and the rest of the set with a road signs practice test for Florida, Texas or California.
The artwork is the federal design itself, which the manual dedicates to the public domain in MUTCD 11th Edition, Part 1, Section 1D.06, checked 2026-09-09. The Interstate Shield, the 511 pictograph and the National Scenic Byway graphic are named exceptions and are not reproduced anywhere on this site.
Source: Manual on Uniform Traffic Control Devices, 11th Edition. Not affiliated with or endorsed by the Federal Highway Administration or any state agency.