Years ago, when my Stuttgart driving instructor told me about Reissverschlusssystem, or “the zipper system, ” I scoffed. The system, now encoded in law, dictates that when two lanes converge, drivers should wait to merge at the last possible point, and then alternately fold together like teeth on a zipper. The zipper rule, aka late merging, is counterintuitive. It violates all sorts of internal norms about waiting one’s turn and sharing the road, and it could even be another instance of Germany’s obsession with rules and efficiency.
And yet? It works — marvelously. Every country should adopt it, including the United States.
My English-born and -bred friend Debbie, who has lived in Germany for 20 years, says it’s just “smoother and more efficient.” But her dad, Brian, who lives back in the U.K., disagrees: On English roads, he likes to block those who try running up the empty merge lane because he thinks they’re cutting the queue. “He’d be fined in Germany” for such vigilantism, Debbie says. But Brits, after all, love to queue and frown on those who don’t, and despite efforts with signs that encourage zipper merges in some places, the driving custom has not taken off in the U.K.
Similarly, American road culture has long dictated that drivers move over to merge at their earliest convenience — politeness that translates into miles of single-lane stoppages while the adjacent lane sits empty. “It’s so wasteful, ” bemoans Leon James, a professor who teaches a course about driving psychology at the University of Hawaii. James also argues that the early-merge system is more psychologically taxing because it forces drivers to hope that they’re let in by others; they might not be. The zipper rule, meanwhile, simply dictates everyone yield at the end.
Only education and public discussions can change people’s minds about late merging.
Studies show it’s more efficient. A University of Nebraska study has shown that the zipper rule can increase merging capacity by as much as 15 percent; others cite as much as 20 percent. And a few states, including Washington and Minnesota, are encouraging its adoption. Ken E. Johnson from Minnesota’s DOT says compliance is getting a little better each year. While more drivers are starting to accept it, he adds, “I still see instances where drivers are not utilizing [it].”
That’s mainly because folks have been taught that it’s impolite, James notes. His students, who debate late merging in class, echo fears that “they won’t let me in” if I go up to the front. Even in Germany, where the zipper rule has been law for 15 years and usually works well, older generations have been known to resist the zipper’s use, according to a representative of its national motor association. And when it’s not used universally, it’s not terribly effective.
Only education and public discussions can change people’s minds. So, from today, boldly go where fellow mergers won’t: up that empty lane. Or, if you refuse, then at least give way to another driver at the merge point. Launch debates at work, post me a nastygram below, and talk about the pros and cons with your teen’s driving instructor. These efforts can help promote a cultural shift in favor of late merging by helping everyone see that it’s less stressful, safer and more efficient … to simply zip ahead.