Located on the edge of the city limits of Wanamingo, Minnesota, the intersection of rural highways TH 57 and TH 60 handles traffic from residents, a nearby industrial park, a farm implement dealer and through traffic. Alliant was contracted to provide preliminary and final design of a new single lane roundabout that addresses the three high-speed approaches, and one low-speed approach connecting the intersection to the rest of town.
Preliminary design tasks included sizing the roundabout and hydrologic calculations to for determination of the construction limits, successfully eliminating the need for any permanent or temporary right-of-way for the project. Using custom AutoTurn vehicle configurations, the roadway designers developed roundabout geometry that can accommodate oversize farm equipment that regularly traverses the intersection. The hydraulic design consisted of storm sewer for the north leg and roundabout, driveway culvert design, and ditch capacity analysis. Alliant’s team completed all work on this project on time and under budget.