Locally (metro NYC), I've heard this referred to as "alternate merge" and it's usually mentioned in the context of someone saying something along the lines of "

Locally (metro NYC), I've heard this referred to as "alternate merge" and it's usually mentioned in the context of someone saying something along the lines of "there was a traffic jam due to an accident and then when it was MY TURN to go, the person in the other lane didn't let me in". Usually there's a comment about how the plates were from out of state, too. This is not to be confused with, e.g., a road that splits and the left lane split it moving fine and the right lane is backed up and a driver in the left lane waits until the last possible second to move over, often times coming to a complete stop, thus backing up what should be a free-flowing lane. No, in that case you didn't move over in time, you don't get to slow down traffic, you take the lane you're in and keep going, you'll have to take the next exit.