DO YOU HATE the Last-Second Lane Cutter? That driver who ignores every neon-orange warning sign that a lane is closing, then zips into line at the last second.

Well, you may need to adjust your thinking: Traffic engineers want you to merge late. Minnesota’s long-running “zipper merge” program reports that using both lanes to the merge point and then taking turns can shrink backups by as much as 40 percent. And a 2024 study sponsored by the Federal Highway Administration found that real-time, electronic zipper-merge signs encourage drivers to actually take turns.

So why the fury? “There’s a misunderstanding between what the rules are and how people actually behave,” says Tom Vanderbilt, author of Traffic: Why We Drive the Way We Do (and What It Says About Us). “We take our notion of ‘cutting in line’ from everyday life into traffic.” —Eric Spitznagel