My April column on the state’s campaign to get drivers to use the zipper merge technique at road construction sites generated quite a bit of buzz. Since then it’s been a hot topic on Twin Cities talk radio and was recently a featured segment on a local television station’s afternoon magazine show.
Motorists have had plenty to say about the driving practice that is included in the latest edition of the Minnesota Driver’s Manual. Over the past couple of weeks, they’ve weighed in with comments and suggestions and questions to keep the discussion going.
Several drivers said communication is the biggest problem in getting drivers to use both lanes until they reach the designated merge point, where they are supposed to take turns to flow safely and smoothly into the remaining lane.
Michael Pagelkopf from Rochester said part of drivers’ confusion is that signs used by the Minnesota Department of Transportation at work zones do not convey a zipper merge, but show a traditional merge.
“How about a sign at the merge point showing what is expected?’ he asked. “You could even make it active showing vehicles moving together to form a single stream of traffic.”
Brian Hoel of Maple Grove suggested ambiguous signs such as “Lane Closed Ahead” so motorists would not know which lane is closed until they reach the designated merge point. Another reader said the zipper merge logo used in ads appearing in newspapers, on websites and on TV should be added to signs that tell drivers to “Use Both Lanes During Backups.”
Spokesman Ken Johnson said MnDOT is looking at ways to modify its supply of signs to better instruct drivers when they should use the zipper merge. One idea is adding the word “ahead” to signs announcing that the right or left lane is closed so drivers know they don’t have to merge immediately.
“Zipper merge is a term we want to throw in there somewhere,” he said. “We are talking with our districts to make sure we are uniform statewide.”
Portable electronic signs with flashing arrows and messages tied to sensors are not always practical because MnDOT has a finite supply and they are expensive.
Cheri Ptack of Eden Prairie wondered if zipper merging is right for non-construction zones where two lanes converge into one, such as on eastbound Hwy. 212 where the left lanes merge into the Crosstown just past Hwy. 169 in Edina.
If a lane drops off, such as on northbound I-35E at Hwy. 110 in Mendota Heights and is marked “Exit Only,” the answer is no, because that lane is supposed to exit. “That would be cutting in line,” Johnson said. Zipper merging is mainly meant for areas where a lane is closed for roadwork.
However, zipper merging might become more common.
Currently, the metro has one intersection striped and signed for zipper merges at all times. That is on the flyover ramp from northbound I-35E to westbound I-694 in Little Canada. MnDOT re-striped the bridge to handle two lanes of traffic because backups often extended into the left lanes of 35E, creating safety hazards.
Johnson said MnDOT is considering zipper merges for traffic control at places such as southbound I-35E to eastbound I-94, and on westbound Hwy. 55 approaching the Mendota Bridge in Eagan.
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