Roundabouts are springing up around Prior Lake to calm traffic and reduce the damage from collisions with their curved paths, Prior Lake City Engineer Andy Brotzler said.
“It’s usually more of an angled sideswipe,” he said. “At traffic signals, you see more T-bones and head-on collisions.”
Prior Lake City Council recently sold bonds for $2.65 million to pay for road resurfacing and to build new roundabouts at the intersection of Highway 21's intersections with Highway 13 and Arcadia Avenue. Construction is set to begin at the end of summer.
With the intersections closed, drivers can take detours to the east on Marschall Road and 140th Street or west along Texas Avenue and 140th, according to the city.
The 13/21 and 21/Arcadia roundabouts will likely be finished in summer of 2020. Another roundabout at Meadow Lawn Trail and Carriage Hills Road should finish late this summer.
A mini-roundabout at Village Lake Drive and Duluth Avenue, just outside the post office, is also under construction through August but is partially navigable now. Assistant City Engineer Nick Monserud said it could be mostly done next week, weather-permitting.
In addition to reducing crash severity, the roundabouts will also create a more even traffic flow on highways, the city officials said.
“At a red light you might sit there with no traffic around you, waiting to go,” Brotzler said. “Roundabouts for high-volume roads can improve efficiency because you aren’t delayed."
Drivers approaching a roundabout must yield to the traffic already in it and enter when their lane is clear. They should then take the curve slowly while keeping an eye out for drivers at other entries.
In two-lane roundabouts, the left lane is primarily for making the equivalent of a left turn at a regular four-way intersection or for a U-turn. Drivers should stick to the right lane if they're taking the first exit for a right turn or continuing straight.
These installments provide a somewhat safer crossing for pedestrians thanks to what Brotzler called a splitter island, a refuge between the two paths of travel. Using this, the pedestrian only needs to watch for traffic from one direction.
While the projects may feel mostly new, roundabouts have existed in various forms for decades around the world and the U.S. Brotzler said agencies like the Minnesota Department of Transportation began evaluating traffic control alternatives at intersections, and roundabouts quickly spread around the state starting around 2000.
“If we look at an intersection that has a four way or a two way stop, there becomes a need for a different kind of intersection control," Brotzler said.
Two roundabouts were constructed in Prior Lake in the late 2000s at the intersection of Fountain Hills Drive and Jeffers Parkway and at the intersection of Fish Point Road and Credit River Road.
Monserud advised residents to be aware of signs and traffic when approaching such an intersection.
"If there's a semi, you'll want to give it some space," he said. "For an emergency vehicle, clear the roundabout as best as you can and pull off to the side."