Zip It: How to zipper merge like a pro
COLUMBIA – When highways narrow at construction zones, interchanges or other bottlenecks, agencies like MoDOT are continuing to encourage drivers to follow the ‘zipper merge’ pattern.
The ‘zipper merge’ happens when two lanes merge into one in areas of heavy traffic. Both lanes have equal right of way, meaning they must take turns at the merge, much like when teeth on a zipper are joined together as the slider passes by.
Simply put - at a zipper merge, drivers should let someone from the neighboring lane in front of them right before they merge, regardless of which lane is technically ending.
“Most motorists start to merge as soon as they see warning signs and learn which lane ahead is closed,” MoDOT said on its website. “When the highway is not heavily congested and traffic is able to move at the speed limit, it is best to merge early into the open lane.”
MoDOT said the zipper merge is necessary when congestion is heavy, in order to maximize available lane space before the merge.
“In dense, slow moving traffic, the open lane fills quickly,” MoDOT said. “Motorists are forced to slow in the closed lane and may become anxious to merge. When a driver in the closed lane can’t move into the open lane in time, the closed lane ends forcing the vehicle to suddenly stop.”
MoDOT said in a situation like this, the driver would have to join fast-moving traffic from a dead stop, which can have dangerous outcomes.
“This driving behavior can lead to sudden lane switching, inconsistent driving speeds that cause crashes, long back-ups and road rage,” MoDOT said. “Research shows these behaviors decrease and traffic moves more smoothly when motorists use both lanes until reaching the defined merge area and then alternate merging every other vehicle in zipper fashion into the open lane.”
According to MoDOT, when drivers follow the zipper merge technique, backups can be reduced by up to 50%.
Right now in mid-Missouri, MoDOT is asking drivers to follow the zipper merge technique at several bridge rehabilitation sites on U.S. 63 between Jefferson City and Columbia.