Kenosha County and the Wisconsin Department of Transportation (WisDOT) contracted raSmith to design the County Y intersection with County A as a single-lane roundabout. This intersection improvement project was funded by the Highway Safety Improvement Program (HSIP) administered through the WisDOT Local Program.
The existing four-leg intersection of County Y with County A operated under two-way stop control (County Y was a free-flow movement) with a posted speed of 45 miles per hour on each approach. The intersection experienced 29 crashes, yielding an average crash rate of 1.41 crashes per million entering vehicles (MEV) from 2013 through 2017, well above the typical average crash rate for rural intersections. Angle crashes were the most common crash type, accounting for 72% of all crashes. Nearly all of these angle crashes involved County A drivers failing to yield the right-of-way at the stop-controlled approaches, resulting in high-speed right-angle crashes.
The purpose of this project was to improve safety at the intersection while maintaining efficient traffic flow on these two county highways. raSmith identified a single-lane roundabout as the safest alternative for the intersection with the potential to reduce crashes by 71%. A single-lane roundabout has been proven to be one of the most successful strategies in addressing angle crashes at rural intersections. Overall intersection operations are also improved with a single-lane roundabout. The roundabout was designed to minimize impacts to surrounding properties while still accommodating emergency service vehicles and standard semi-trucks for all movements.