Don't get mad at drivers who stay in an ending lane and merge at the very last second. They're actually doing the right thing and zipper merging.
GoMN spent some time riding around with Ken Johnson, a Minnesota Department of Transportation work zone, pavement markings and traffic devices engineer. He explained how zipper merging works and why officials want you to do it.
Basically, it helps reduce backups when a lane has to end (due to something like construction) because traffic remains spread out over multiple lanes for as long as possible.
It's also safer because traffic in all lanes keeps moving at around the same speed. Johnson explained that having slow traffic in one lane and fast-moving vehicles in another increases the risk for crashes.
It's important to note that you can't always zoom past traffic and call it a zipper merge. Say there's a major backup on a regular exit lane and someone speeds ahead to right before the lane branches off and cuts in.
That's not a zipper merge. That's just being a jerk.
Watch the video above to see exactly how zipper merges work. You can learn more here.
We also did a video on how not to drive like an idiot in a multi-lane roundabout.