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.”
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.
The 16- to 18-month study will compare three alternatives: Adding a permanent fourth northbound lane to Cedar, in the form of a MnPass lane, from 138th Street in Apple Valley to Old Shakopee Road in Bloomington, using some of the median of the highway and the shoulder on the river bridge; building a MnPass reverse-flow zipper lane between Apple Valley and Bloomington using one of Cedar’s southbound lanes; and a combination of the two, with a MnPass lane starting on the northbound side of Cedar in Apple Valley, then crossing over the freeway median at Diffley Road in Eagan into a zipper lane up to Bloomington.
A new lane to assist the southbound lanes in the afternoon is not under consideration because the evening rush hour is more spread out and congestion is not as intense, Solberg said.
There’s also a concern that adding a lane in the southbound direction would pipe congestion into downtown Apple Valley.
A key question is whether the traffic from the contra flow lane can be added back into northbound traffic at Old Shakopee Road without bogging down traffic there and at I-494.
“We don’t want to create more of a headache than we are trying to solve,” Solberg said.
Staff and elected officials from Dakota County, Apple Valley, Eagan, the Minnesota Valley Transit Authority and Metropolitan Council are serving on advisory groups for the study and would be expected to come to consensus on a preferred plan that MnDOT and the county would recommend to Federal Highway Administration.
Egan said he prefers an alternative with as little shifting of traffic as possible as well as an improved design for the Cedar Grove station access.
Apple Valley City Council Member Clint Hooppaw said congestion on Cedar creates problems for the Apple Valley business district.
“Not only do we want the bottleneck out of Apple Valley, but we want people to get to their destinations quickly. I wish it wasn’t 18 months of more discussion. I wish we could move quickly.”
Because it would be the first zipper lane in the state, Hooppaw said he has some concerns about how it would operate in a big snow.
Possibly making the extra lane a MnPass pay lane is an option the city is willing to accept, Hooppaw said.
Some people are saying “I just want to get north more quickly and I don’t care about [having to pay] the buck and a half.”
Laurie Blake • 952-746-3287