Ann Arbor agrees to split cost of new roundabout at State and Ellsworth with Road Commission

The agreement spells out that the Road Commission will design and construct the project, acquire all necessary permits, and provide the construction engineering services.

One of the reasons cited for the roundabout is the opening of a new Costco store just west of the intersection in Pittsfield Township at the end of June.

The total project cost is estimated to be about $2.5 million. The Road Commission has secured a Congestion Mitigation and Air Quality grant from the Federal Highway Administration in the amount of $1.4 million and Costco plans to contribute $500,000.

With the exception of any landscaping, decorative concrete or public utility upgrades, the Road Commission and the city will split the remaining costs for the roundabout. The city will be solely responsible for all costs associated with public utility upgrades.

When constructed in 2013, it will be the 10th roundabout in the county. It’s expected that construction would begin next April or May and be completed by Labor Day.

"I think it's a significant change," said Council Member Jane Lumm, an Independent representing the 2nd Ward.

Council Member Marcia Higgins, D-4th Ward, said her only concern is the ability of large trucks to navigate it without forcing other drivers out of the way.

The Road Commission already contracted with DLZ Michigan Inc. to design the roundabout and prepare detailed construction drawings and specifications.

Homayoon Pirooz, head of the city's project management unit, said the design is still in the preliminary engineering phase. Items being considered that may be added include landscaping in the center island and decorative concrete, he said.

As designed now, the roundabout is 150 feet in diameter with all intersection approaches having at least two lanes to accommodate traffic entering and exiting.

The southbound approach on State Street includes a third lane that allows the anticipated high volumes of right-turning traffic onto westbound Ellsworth to bypass circulating traffic.

Other project features include non-motorized paths in all intersection quadrants that connect with the existing sidewalk system and new on-road bicycle lanes, street lighting, and underground electrical conduits for the future addition of HAWK or Rectangular Rapid Flashing Beacon signals at the crosswalks should they be required.

The city will be replacing a 20-inch water main within a portion of the project limits. That's a transmission main that transports untreated water from the Steere Farms wells on the Ann Arbor Municipal Airport property to the Water Treatment Plant.

That work was to have been part of a larger future capital project. It was accelerated and incorporated into the roundabout project to avoid future disruption to the intersection.

Area residents voiced a mix of support and concerns about the roundabout when The Road Commission held a public meeting on Feb. 29.

The Road Commission and the design team from DLZ spent 90 minutes answering numerous questions about the project. Pirooz said a second meeting is planned prior to the start of construction that will cover more of the project details.

Pittsfield Township Supervisor Mandy Grewal recently said she's ensuring that seniors will receive instructional presentations on roundabouts, including practice rides in cars.

Pirooz said there already are capacity and traffic operational issues causing delays at the intersection, which is jointly controlled by the city and the Road Commission.

Given the amount of traffic that's already there, and the increased traffic that will result from the opening of a new Costco, officials believe the best solution is a roundabout.

Recent traffic studies indicate that continued growth and development will further compound the issues and impede the functionality of the intersection, Pirooz said.

Early analysis by DLZ compared a traditional signalized intersection improvement with a modern roundabout and revealed that a roundabout is a better alternative.

A more detailed examination determined a two-lane roundabout would best accommodate the traffic projected at the intersection.

Pirooz said the city had difficulties getting the traffic through the busy intersection about 10 to 12 years ago and it added more lanes then.

"It worked fine for a little bit of time," he said. "Now with all of the development, especially Costco going to the neighborhood, I cannot think of any good traffic signal that would handle that amount of traffic."

Based on the engineer's estimate, the city's share for the improvements at the intersection is $135,000. Pirooz said the final numbers likely will be different. He estimated it will cost another$350,000 to replace a section of an older water main.

Council Member Margie Teall, D-4th Ward, was absent Monday night.