Nicollet County roundabout eases traffic, ensures safe access to high school

A new Nicollet County concrete roundabout eases traffic on Broadway Street (CSAH 5) in Peter, Minn. The impetus for the project was the construction of a modern, new St. Peter High School on this street at the edge of downtown. The school opened in September 2017.

The highway has heavy truck traffic, and the speed limit is 45 mph from the east and 55 mph from the west. The county worked with the St. Peter School District and the City of St. Peter on how to slow down the traffic and allow safe access to the school.

“Speed was a real concern, especially since we have young drivers and quite a few students who walk and bike to school,” said Nicollet County Engineer Seth Greenwood. “Rather than having traffic going 55 mph, we had to consider how to get that to slow down.”

Roundabout eases traffic yet keeps it flowing

When the school district held public open houses in 2016 to talk about the bond referendum for the new high school, county representatives were there to describe the roundabout solution. A feature of the roundabout design is long, curved medians that force drivers to reduce their speed.

“We’ve heard positive feedback from residents and it seems to be working extremely well,” Greenwood said.

A related project involved a township gravel road that leads up to the roundabout from the south. The township and city received local road improvement funds and replaced the gravel with bituminous at the same time the roundabout was constructed.


The 1.14-mile CSAH 5 project stretches from 361st Avenue to Sunrise Drive. The entire project was paved with 7-inch, doweled concrete for long-term performance of the pavement.

Broadway Street on the west side of the project was already paved with concrete. The urban side was paved with 25-year-old bituminous that was in tough shape. The county milled that out and replaced it with concrete. Also, it rehabilitated some curb and gutter, updated ADA ramps, and performed soil correction in the roundabout area.


$3 million: The county paid $2.1 million, and the city and school district put in $900,000.


May 2017 – August 2017.  They had to finish before the new high school opened right after Labor Day.


Owner: Nicollet County • Project designer: Stonebrooke, Burnsville • Contractor: Mathiowetz, Sleepy Eye • Subcontractor: Hoffman Concrete, Mankato • Ready mix producer: Cemstone

Check out a different 2017 St. Peter case study: Broadway Street reconstruction project.

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