According to city Engineer Tyler Bumbalough, an initial study was performed shortly after the roundabout was installed in September 2009. The study noted that the right-hand turn bypass lanes were misaligned. Some local officials also wanted the roundabout to be higher functioning for pedestrian walk-ability, safety and slowing traffic speeds within the roundabout.
“We had known that this was a temporary type roundabout when we initially put it in in 2009,” said Bumbalough. “We took down the traffic signals and installed paint within the square, but that’s not what a modern roundabout is. A modern roundabout includes features such as islands and better crosswalk designations to help deter traffic, slow it down, and traffic calming techniques that really help geometrically slow the traveling public down.”
Bumbalough said the city plans to bid the project in January or February 2019, with a contractor starting work in March or April. The contractor must have everything within the pavement limits complete by Aug. 31, after which ODOT will execute an existing contract to pave the square and one block in each direction from the square: Court, Market, Walnut and Locust streets.
“There’s going to be five maintenance and traffic phases,” Bumbalough said. “The first phase will address the improvements in the center of the square. The next four phases will have leg closures, so the south leg might be closed at one time with some of the parking area on one side or the other, then they’ll move on to the next leg and do one side of the parking or the other. Those blocks will be closed, except to pedestrians, and they’re going to try to maintain traffic to the parking lots and alleys with just a narrow strip to get to those.
“We’re not closing down downtown in the sense that we’re closing businesses,” he added. “We’re keeping businesses open. They’ll have pedestrian access to them, though they won’t have parking necessarily when that leg is closed. The contractor must maintain access to the storefronts. If the concrete has to be replaced in front of the entry then the contractor will work with the store owner for any alternatives.”
In advance of construction there will be notice of closure signs posted two weeks prior to construction. Both truck detours and internal detours within the city will be posted during construction. At the request of the city’s fire and police divisions, emergency personnel will still be able to get through the closed legs, Bumbalough said.
Bumbalough said the Monument Square roundabout takes over 25,000 vehicles a day, which is why the city is phasing the project to create the least disturbance.
“Roundabouts decrease the severity of accidents, and they also cut down on the number of conflict points,” he said. “I think there’s only eight conflict points in a single lane roundabout. In (a nonroundabout) intersection I think there’s over 20 conflict points where you could have a series of different kinds of accidents. There’s no real opportunity for T-bone crashes as much as there are for just sideswipes or rear-ends in a roundabout, so we wanted to decrease severity of accidents.”
Accident numbers within the roundabout have steadily decreased since its installation as people have gotten used to it, Bumbalough said, adding the coming upgrades are intended to decrease accidents even further.