Aside from accidents and rubber-necking, forced merging—usually caused by road construction—is one of the main causes of traffic jams. It doesn’t have to be that way. Sure, there’s a reduction of capacity on the road or freeway, but most often the reason for the back-up is that drivers don’t know when exactly to merge.
Some transportation departments are trying to steer drivers in the right direction. “Zipper merging” is the favored term for appropriate merging, which calls for cars to remain in their lanes as long as possible. While many cars begin moving into the shared lane at the first indication of a merge, zipper merging says to keep utilizing all lanes until the merge-point is reached (from above, the motion looks like a zipper).
A video from the Minneapolis Department of Transportation, via The New York Times, says that merge signs are simply warnings that is a change is approaching—not a directive that drivers must merge at that exact moment. By not merging early and making use of the multiple lanes as long as possible, traffic can be reduced by 40 percent. It also minimizes road rage, apparently.
The Kansas DOT put out their own zipper merge video—with stoned-looking animated orange cones—that explains the process succinctly and stresses the fact that the zipper merge is imperative when traffic is heavy (when it’s light, merge whenever you want). The video also addresses the ethics of what can be seen as jumping the line or cutting in front of other cars.
“But, you know if you have two lanes coming up to that merge, then there’s no long line to cut in front of, is there?,” says the wise cone.