[gbhn]

The point of the article is that your intuition is incorrect. By inhibiting zipper merging you are forcing congestion backward, and leaving carrying capacity of the road unutilized during congestion when it is most at a premium.

Pushing congestion backwards is exactly the cause of a lit of traffic jams. I've observed this myself every single GD day on the 210W freeway between Hill exit and the 134 exchange. People get over way early, causing huge congestion to the merge entrances. If they'd stay left and zipper, everyone in the jam would save about 5-10 minutes. This is thousands and thousands of dollars a day of cost in completely avoidable congestion in just one two mile stretch of highway ( albeit it a particularly egregious one)