What does the Added Lane sign mean?
The Added Lane sign (MUTCD W4-3) is a warning sign under the federal Manual on Uniform Traffic Control Devices, the national standard the states build from. A whole extra lane opens on the entry side, so joining traffic has somewhere to go and nobody has to change lanes or yield.
Source: MUTCD 11th Edition, Chapter 2C, Table 2C-1, checked 2026-09-09.
What shape and color is the Added Lane sign?
| MUTCD code | W4-3 |
|---|---|
| Group | Warning signs |
| Shape | Diamond |
| Color | Yellow background, black symbol and border |
What a diamond means. A warning. It tells you what the road does next and obliges you to do nothing in particular, which is the distinction test writers probe most often.
What yellow means. General warning of a permanent condition ahead.
Warning signs. A diamond reports a condition and orders nothing. What you do about it is left to you, and that gap between a report and an order is what test writers keep probing.
What is the Added Lane sign often mistaken for?
Merge (W4-1). Candidates say they must yield; with an added lane there is nothing to yield to.
|  |
|---|---|
| GroupWarning signs | GroupWarning signs |
| ShapeDiamond | ShapeDiamond |
| ColorYellow background, black symbol and border | ColorYellow background, black symbol and border |
| What it meansA whole extra lane opens on the entry side, so joining traffic has somewhere to go and nobody has to change lanes or yield. | What it meansTwo traffic streams join ahead and drivers on both must adjust speed and position. |
What does the permit test ask about the Added Lane sign?
This question is from the practice bank, with the answer marked.
This sign means:
- A.A lane is added, so joining traffic does not have to merge into yours(correct answer)
- B.Your lane ends ahead
- C.A passing lane is closing
- D.Traffic ahead is merging into a single lane
Source: MUTCD W4-3
What are the other warning signs?
All 55 warning 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.