But that wouldn't be the zipper merge, now would it? The zipper merge is: each car in the lane continuing lets one car in. Just one. That is how a zipper works.

If the car in front of you is letting in 2-3 cars, you'd be right to be pissed, because that is not the zipper merge. Similarily, if a second car tries to squeeze in after the one car you let in, that second driver is a dick.

I have no idea why Medium decided today I was to get this 2 month old article. I barely drive nowadays and here in Austria as in many other countries I note in the comments, the Zipper merge works. I wouldn't say perfectly, as Austrian men are often dicks when they drive, but it works quite well.