Twenty years of removing bottlenecks on the metro freeway system has demonstrated that relieving one chokepoint often just speeds traffic to another one farther down the road.

With that in mind, the Minnesota Department of Transportation has ruled out adding a lane to speed up the morning commute on northbound Cedar Avenue until it first adds a lane to westbound Interstate 494 to handle the Cedar traffic.

Cedar, or Highway 77, is a favored north-south commuting option for residents of some of the south metro’s most densely populated suburbs. The Met Council says more than 155,000 vehicles travel along Cedar Avenue daily, and that number is expected to double in the next 20 years.

MnDOT traffic models show a new lane on Cedar might get drivers through Apple Valley and Eagan faster, but they would then pile up in Bloomington at the junction to I-494, negating the time they saved with the new lane.

How and when to add a lane to Cedar will be one of many issues to be considered when MnDOT launches a major study of the I-494 freeway ring early next year, said Metro District Engineer Scott McBride. “It’s one of the bigger studies we have undertaken.”

Starting in January or February, the department plans to spend up to 18 months and more than $1 million examining whether to add MnPass express lanes to 494 starting at the Minneapolis-St. Paul International Airport and going through Richfield, Bloomington, Edina, Eden Prairie and then north to Minnetonka and up to Maple Grove. From there the study will continue on Interstate I-94 from Maple Grove to Rogers.

50 percent more riders

MnPass lanes are express lanes for buses, carpools and motorcycles and solo drivers willing to pay an electronic toll. MnDOT favors the lanes as a way to address traffic congestion because they offer an alternative to sitting in heavy traffic and carry 50 percent more people than regular lanes. The 494 corridor does not have any MnPass lanes now.

The purpose of the study is to establish a plan for how to improve 494 over time and prepare the department to build stretches of MnPass lane as funding and opportunities are available, McBride said.

The outcome of the 494 study may give a clearer idea about when Cedar Avenue improvement could be expected.

Officials representing Apple Valley, Eagan, Bloomington and Dakota County have been studying options for adding a MnPass lane to Cedar Avenue to address growing congestion on northbound Cedar.

In June, the metro area’s first Bus Rapid Transit line, known as the Red Line, started running along Cedar Avenue. It extends 11 miles south from the Mall of America in Bloomington, through Eagan and Apple Valley.

Idea to use shoulder

Next month, the south suburban advisory group is expected to recommend slightly widening the highway and using the shoulder to create a northbound-only MnPass lane on Cedar. The lane is estimated to cost $47 million.

Westbound I-494 would need an extra lane added on the right as a direct entrance from northbound Cedar in order for the Cedar MnPass lane to pay off in terms of time savings, traffic modeling shows.

People are anxious for traffic improvement on Cedar, said Dakota County Commissioner Tom Egan, who is serving on the Cedar advisory group. Knowing that the metro freeway system is interconnected, he said he is not surprised or disappointed to hear that Cedar improvements will be contingent on I-494 improvements. But, he said, he wants the advisory group’s recommendation on the Cedar MnPass lane location to stick, regardless of how much time passes before it’s implemented.