Baton Rouge drivers know the backups all too well, with frustration going farther than the vehicles themselves.
But traffic experts say zipper merging can ease the congestion, so long as motorists know what to do.
Zipper merging happens when a lane closes. The idea is that cars in the shuttering lane alternate forward with those in the open lane. If done right, the vehicles move like teeth on a zipper.
Proper practice relies on the kindness of drivers. DOTD spokesman Rodney Mallett says too often, motorists refuse to let cars into oncoming traffic, because they think drivers in the closing lane are trying to cut the line. Other drivers merge before the lane closure, causing more congestion.
Louisiana has no laws enforcing proper zipper merging, though lawmakers in Washington and Minnesota have suggested them. Germany requires motorists to alternate at zipper merge spots.