Sunday, July 27, 2014

Reducing traffic jams through ruder merging

Of all of the reasons for traffic snarls, impending lane closures bring out a particularly brutal combination of road rage and etiquette confusion. Most drivers know the pain of approaching two lanes in this situation; the left one is backed up much further because the right one will close in less than a mile thanks to, say, construction.

Which lane should a driver pick in this scenario? Steer to the left as soon as you see a closure notice and you'll almost certainly go slower; stay in the right and you'll catch stink-eye, honks, and even swerving drivers. Everyone is upset that you're about to essentially cut in line—an act that will require a tense, last-minute merge of your own. ...

This week, however, Washington state joined Minnesota in sending a clear message to drivers: merge rudely. It's actually faster and safer.

There's a name for it: late merging, though advocates prefer the term "zipper merging" because it doesn't have a negative connotation. ...

It works as follows: in the event of an impending lane closure, drivers should fill in both lanes in equal measure. Within a few car lengths of a lane ending, both lanes' cars should take turns filling in the open lane and resuming full speed.

If roads are clear enough that everyone is already driving close to the speed limit, zipper merging isn't as effective, but in the case of congestion, Johnson said that this method reduces backups by a whopping 40 percent on average, since both lanes approach the merge with equal stake in maintaining speed. "When the queue backup is reduced, the access points behind a work zone, like signals or ways to get on and off the freeway, those aren’t blocked," Johnson pointed out. "People have a better opportunity to get off or on the system at that point.
--Sam Machkovech, Ars Technica, on inefficient etiquette. HT: Marginal Revolution