Two new roundabouts coming on Highway 30 in Mount Vernon

Corridor motorists will be seeing their first roundabouts on a federal highway in 2012.

The Mount Vernon City Council approved construction of two traffic roundabouts on Highway 30 after a heated community discussion about adopting the unfamiliar traffic control designs.

Roundabouts will be constructed at the intersection of Highway 1 and Highway 30, and at the intersection of 10th Avenue and Highway 30, at an estimated cost of $1.6 million, City Engineer Dan Boggs said Friday. Construction would be  in the summer of 2012 at the earliest, Boggs said.

The council voted 3-1 late Thursday night to proceed with the roundabout plan, which was proposed by an engineering consultant to slow traffic speeds,  address peak-hour traffic backups at the Highway 1/Highway 30 intersection and improve safety.

Opponents had favored traffic signals at the interchanges. Some of them said the continuous flow of traffic through  roundabouts would not allow enough traffic “spacing” for motorists to turn into businesses along Highway 30, and that they could be difficult for large trucks to navigate.

Diane Hoffmann, the lone city council member to vote against the measure, said her primary concern was cost rather than traffic dynamics.

“My concern is that City of Mount Vernon will be funding $600,000 on a project which will provide a short term solution to the current traffic congestion and will divert scarce financial resources from needed street repair within the City of Mount Vernon,” Hoffmann said in e-mailed remarks.

Hoffmann She said she'd prefer that the Iowa Department of Transportation lower the speed limit to 30 miles per hour and that it assume the financial cost for controlling traffic at the Highway 30/Highway 1 intersection.

Much of the state funding the city has received for the improvements cannot be used for traffic signals, but can be used for roundabouts. The DOT has so far been unwilling to lower the speed limit to the 30 m.p.h. level.

The project was scaled back to exclude plans to widen the highway to four lanes with sidewalks, curbs and other urban amenities. Cost was the major concern, City Administrator Mike Beimer said. He said the project will include some visual upgrades such as landscaping as the project develops.

The Iowa Department of Transportation strongly supported the roundabout option, saying roundabouts have been shown to be safer than signalized intersections and effective at reducing traffic speeds.

The DOT is still making plans for a bypass of  Mount Vernon and Lisbon on Highway 30, but the project is not funded in the DOT's five-year highway plan.

The DOT will hold a public meeting on plans for the U.S. 30 Mount Vernon-Lisbon bypass on Thursday, March 10 from 4:30 p.m. to 6:30 p.m. at the commons of the Mount Vernon High School, 731 Palisades Road SW. No formal presentation will be made. DOT staff members will be on hand to discuss the project plans and status.