Going round in circles: City intersection picked for mini-roundabout project

Graphic courtesy of Washington County Public Works
This rendering from the Federal Highway Administration shows how the mini-roundabout would fit at the Owens and Myrtle streets intersection. County officials stressed Tuesday this drawing is not the final design for the proposed mini-roundabout.

A busy Stillwater intersection would be one of 10 federal tests of a new mini-roundabout design, a Washington County Public Works official told the Board of Commissioners Tuesday.

Traffic Engineer Joe Gustafson said the Owens-Myrtle streets intersection was one of two intersections in Minnesota cities picked by the Federal Highway Administration to the project. The other site is in Shakopee.

Gustafson said the FHWA pays for 90 percent of the intersection design and construction costs up to $100,000. In exchange, the county agrees to leave the roundabout in place for three years.

The intersection of Owens (CSAH 5) and Mrytle (CSAH 12) streets was picked for the mini-roundabout test project because of it current setup as an all-way stop with little space between the roads and sidewalks and on-street business and residential parking, Gustafson added.

“You can have as many as eight cars coming up to this intersection wondering what to do,” he said, adding that there are few breaks in traffic during peak congestion periods.

“We expect it will get worse over time,” Gustafson said.

Installing traffic signals at Owens and Myrtle comes with other issues, he noted.

“Why can’t we just put in a stoplight? We could, but it comes with significant drawbacks,” he said.

They include difficulty fitting signal poles at the site; poles being unsafe with the existing lane arrangement; left turn lanes would lead to significant loss of parking, and the narrow streets and signals causing worse traffic delays, according to Gustafson.

The intersection, however, fits the FHWA idea for a mini-roundabout that Gustafson said is smaller than the existing intersection. He adds that the proposed mini-roundabout would have a smaller diameter; no island landscaping or signs; is appropriate for a low-speed road; minimizes loss of parking; decreases traffic delays; improves traffic gaps with nearby intersections; offers better pedestrian visibility and wider sidewalks, and is less expensive than installing traffic signals because the county would not have acquire land for the project.

Gustafson said the proposed Owens-Myrtle roundabout also creates a safe environment for both vehicles and bicycles.

“It’s a little bit chaotic,” he said about vehicle and bicycle traffic at the intersection. “One thing with the roundabout is that it brings vehicle speeds down to where it’s cohesive with bicycles.”

Gustafson said the county does not have to accept the federal grant for the project. If the county uses the FHWA funds, the county must follow federal rules for the project.

Gustafson said WCPW officials have discussed the Owens-Myrtle mini-roundabout with Stillwater city officials and will present the idea to the Stillwater City Council at the group’s Tuesday work session. He added that county officials plan a future public open house to explain the roundabout idea.

If the county accepts the federal grant, the Owens-Myrtle mini-roundabout design will be refined and construction tentative scheduled to being in spring 2014, Gustafson said.

And if county and federal officials discover the Owens-Myrtle mini-roundabout does not work? Gustafson said there is an easy fix.

“What if the models are wrong? If for some reason this doesn’t work, we can come back and take that island out,” he said. “We could return it to the current configuration.”

 

Graphic courtesy of Washington County Public Works

This rendering from the Federal Highway Administration shows how the mini-roundabout would fit at the Owens and Myrtle streets intersection. County officials stressed Tuesday this drawing is not the final design for the proposed mini-roundabout.