The yellow diamond with two lanes joining into one warns that traffic will be entering your roadway ahead, typically from a ramp on the side the symbol shows. Both the through driver and the entering driver get the warning: one should adjust to make room, the other should match speed and find a gap.
A merge is a cooperation problem, and the sign starts it early. On the through road, check your mirrors, and where it is safe, move over a lane or adjust speed so the entering traffic has a usable gap. Entering drivers do not have the right of way; the sign does not change that.
If you are on the through road, check mirrors and blind spots, and open a gap by adjusting speed or changing lanes when safe. If you are the merging driver, use the ramp or acceleration lane to match the speed of traffic and merge into a gap; do not stop at the end of the lane unless there is truly no gap.
It is regularly confused with Lane Ends, which means one of the existing lanes on your own road is ending and its traffic must move over, and with Added Lane, where the joining road gets its own lane and no merge is needed. The arrows tell the story: joining arrows mean merge, a narrowing lane means lane ends, and parallel arrows mean added lane.
This sign appears in 20 questions across 20 of our state banks, on Driver License practice tests. Start with your state:
What roadway condition does the displayed merge warning announce?
Why: The merge warning sign alerts a driver to traffic entering from the indicated side and calls for heightened observation and adjustment. Therefore, the proposed response is "Traffic may enter your roadway from the side".
Every practice test explains its answers this way. Pick your state and take one free; no sign-up.
Choose your stateTraffic will be joining your roadway ahead from the side shown, usually a ramp. Through drivers should open a gap where safe, and entering drivers should match speed and merge into it.
Traffic already on the through road. The entering driver must find a gap and adjust. Courtesy from through drivers helps, but the legal duty to yield sits with the driver entering.
Merge means outside traffic is joining your road. Lane Ends means one of your road's own lanes is disappearing and its traffic must move over. Test questions swap them because the situations feel similar from the driver's seat.
Check mirrors and your blind spot, and if the adjacent lane is free, move over to give entering traffic the lane. If you cannot move over, adjust speed slightly so a gap forms. What the test never accepts is holding position and speed as if the ramp were not there.
Only as a last resort with no gap at all. The acceleration lane exists for matching traffic speed; stopping in it turns a merge into a standing start into fast traffic, which is far more dangerous.