MnDOT looks at reversing Cedar Avenue lane in Apple Valley, Eagan to relieve traffic congestion

  • Article by: LAURIE BLAKE , Star Tribune
  • Updated: February 21, 2013 - 11:20 PM

Metro’s first “zipper” lane on Cedar Avenue is a new approach.

South-metro commuters weary of fighting their way north on Cedar Avenue may get an extra lane for weekday mornings.

The Minnesota Department of Transportation (MnDOT) is studying the possibility of turning one of the southbound lanes into a northbound lane during morning rush hours, blocking it off with a temporary barrier. It would be the metro area’s first reverse-flow “zipper” lane.

It’s an ideal road to try such a lane because a huge majority of morning traffic on Cedar heads north, the department says. With 80 percent of the traffic on the freeway heading north during morning rush hours, one of the lesser-used southbound lanes could become a northbound MnPass lane for buses, carpools, motorcycles and solo drivers willing to pay the posted fee.

For a reverse-flow lane, the ideal is a 60-40 split to ensure there is enough spare capacity to safely borrow a lane to reduce congestion, said Jon Solberg, MnDOT’s south area planner. With an 80-20 split, “we really have a big differential on the corridor that allows us to do that.”

The lane would be created by a line of movable concrete barriers that would separate north and south traffic.

The barriers, linked by steel connectors, would be moved back and forth from the shoulder with a barrier-transfer machine known as a zipper machine. The action of the truck moving the barriers looks like the opening and closing of a big zipper.

Zipper lanes are already in use elsewhere around the country.

Cedar, a key commuter route also known as Hwy. 77, carries an average daily traffic load of about 73,000 vehicles, about 14,000 of which are heading north in the morning.

Drivers from Lakeville, Apple Valley and Eagan drive the freeway to jobs at the Mall of America, along the Interstate 494 strip and in downtown Minneapolis, creating one to two hours of congestion every day.

Two bottlenecks slow traffic between Apple Valley and I-494: the bridge over the Minnesota River and a two-lane stretch between 138th Street and Diffley Road; Cedar otherwise has thee lanes in both directions.

Traffic routinely backs up four to five miles south of the bridge, then typically loosens north of the bridge as vehicles fan to east and west I-494 and other points.

Dakota County Commissioner Tom Egan, who is serving on the advisory group, said south-metro residents are eager for help with congestion on Cedar.

The lane drop near 138th Street that leads into the two-lane section causes anger and frustration, Egan said.

“I know people who drive it every day and they are still confused,” he said. “There have been a lot of close calls.”

Three options

Seeing the potential for congestion relief, MnDOT is now doing preliminary engineering to study the cost and benefit of a zipper lane.

The $600,000 in pre-engineering work will include designing a better exit from and entrance to Cedar from the Cedar Grove bus stop in Eagan. That bus stop will be used by the new Cedar Avenue bus-rapid transit (BRT) line, which will open in May or June.

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