Tell that to the site linked above, because even though they say "like a zipper" they want it to happen early.

> The problem is that if some cars merge too early, other cars will keep driving down the road and then merging in front of the early mergers, it ends up being disruptive in heavy traffic conditions. If everyone consistently merges at the same point in heavy traffic conditions it's more predictable, leading to better through flow.

I don't blame the early mergers there. If someone zooms down the empty lane then they are not attempting to zipper merge, they are bad actors.

A proper zipper, at the last moment, is slightly better than early merging. But again smoothness is the important factor. Smoothness is 90% of the solution. Do not give up smoothness for the sake of being more zipper-y. If people think you're cutting in line, you probably are cutting in line.

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Also, anywhere we want to make sure there's a zipper merge, how about we stop having a favored lane? Cut off half of each lane at the merge point.

Good point, even in a situation that necessitates a favored lane, could still setup this half-of-each-lane merge point well in front of that.