Warning signs
Added Lane sign
An extra lane is about to begin, usually where a ramp joins the highway as its own lane rather than requiring a merge. No one needs to change lanes.
- Diamond
- Yellow
- MUTCD W4-3
Shape and background first
Federal designation W4-3 in the MUTCD, the national standard every state signs to. Typically seen where a long highway on ramp is engineered to become a permanent through lane rather than dissolve into existing traffic.
What the MUTCD specifies
Designation: W4-3
MUTCD Section 2C.46
Conventional road size: 36 x 36 in
Source: Federal Highway Administration, MUTCD 11th Edition (December 2023), Part 2, Table 2C-1, verified 2026-09-26.
What the test wants you to know
The mistake people make
The symbol shows two separate arrows running side by side into two continuing lanes, which is what sets it apart from a merge sign where two arrows become one. Because both lanes continue, entering traffic does not carry the right of way the way a true merge grants it, though courtesy still applies.
The sign people confuse it with
Added Lane gets mixed up with Merge more than any other pairing in this category. Put them side by side and the difference is obvious, which is exactly why it is worth doing once rather than meeting them cold in the exam.
Added Lane
An extra lane is about to begin, usually where a ramp joins the highway as its own lane rather than requiring a merge.
Merge
Traffic from another roadway will join yours.
