re: A reminder that zipper merging is how your supposed to handle merging

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What "everyone in one lane" adopters fail to realize is that at some point, everyone MUST move from the right lane to the left lane and by doing it willy-nilly, you create more conflict points. It's better to have it at one single point and use the full road storage up until that point.

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No, no, no. A single conflict point is bad, and using the "full road storage" is bad.

If there is one conflict point where everyone merges, if it's going to be efficient then it has to work like clockwork. Everyone has to be on point and accelerate precisely right. This does not and will never happen, and trying to do this *causes* the "full road storage" situation. It creates a humongous conflict point, and every vehicle has to slow to a crawl or stop.

Merging early allows most vehicles to merge with no conflict at all. Just merge when you can. It's less of a bottleneck and more of a long funnel. And by the time the vehicles reach the choke point they are moving faster and keep things moving.

I don't know how these supposed studies and models were done which claim to prove zipper merge is best, but if one of the objectives is to treat the road as vehicle "storage" then it is flawed from the start. Roads are for moving cars, not storing them. Keeping cars moving requires speed, not precision merging.


Think about it like this, starting with 2 lanes jam packed at a dead stop for a mile. To simplify, the one open lane ahead is wide open, and there are no new vehicles adding to the back of the lines. What's the fastest way to clear this jam? Not the zipper merge, and not by a long shot. The fastest way is to tell everyone in the open lane to go as fast as they safely can go, then once that lane is empty tell the blocked lane to go ahead and move over and go as well. We can make it faster if those in the rear of the blocked lane start moving over and going as soon as they can instead of going in the present order. This would clear the jam much, much faster than a zipper merge. Why? Because we eliminated the damned choke point and pretended it was a 1 lane highway. The zipper merge not only maintains the choke point, but it forces every single fricking vehicle to deal with it at slow speed.

Now, of course things change if the single lane ahead is backed up, and we also have to consider what is happening behind the jam as well. But if we want raw efficiency at moving vehicles, we need more cars per second through the choke point and that requires speed. Zipper merge is far from ideal.