After years of planning, months of construction and a history of deadly crashes, a major safety improvement near Marcus is ready for its official celebration.
The Iowa Department of Transportation (DOT) is hosting a ribbon-cutting ceremony on Wednesday for the newly constructed roundabout at the intersection of Iowa Highways 3 and 143, just south of Marcus.
The event, called the “Roundabout Rally,” will celebrate the completion of Cherokee County’s first modern roundabout — while giving drivers a chance to learn how to safely navigate the new intersection.
The ribbon cutting begins at 10 a.m. at Casey’s, located at 406 Highway 3 in Marcus, with refreshments provided. Beginning at 10:30 a.m., Siouxland Regional Transit System will offer educational bus tours through the roundabout, departing every 15 minutes until noon. The tours are designed to help both new and experienced drivers become more comfortable with the new traffic pattern.
The roundabout represents a major investment in highway safety, with approximately $4.55 million programmed for the project in Iowa’s 2026 Statewide Transportation Improvement Program, including federal and state funding.
But improving safety — rather than simply moving traffic more efficiently — has been the driving force behind the project.
The former four-way intersection had a history of serious and fatal crashes, including a 2020 collision that killed 26-year-old Alexa Brewster of Cherokee.
Iowa DOT District 3 Transportation Planner Sarah Tracy previously said that the roundabout was selected because it significantly reduces the risk of high-speed, right-angle collisions — among the most dangerous types of intersection crashes.
According to the Iowa DOT, roundabouts reduce crashes overall by approximately 40%, while reducing serious crashes by approximately 80%.
Unlike traditional intersections, where vehicles can cross directly in front of oncoming traffic, roundabouts require drivers to slow down and yield to vehicles already circulating through the intersection.
The Marcus roundabout is also notable for its size. It’s designed as one of Iowa’s largest single-lane roundabouts, with a wide diameter and features that allow semitrailers, farm machinery and other oversized vehicles to safely maneuver through the intersection.
The project has been years in the making. The Iowa DOT sought public input on the proposed redesign in 2024, with construction getting underway this spring.
Work progressed through multiple stages over the summer and fall, including the closure of Highway 143 beginning in late August. Drivers were required to follow detours while crews completed the final stages of construction, and Highway 3 traffic was restricted to a single lane controlled by temporary traffic signals.
Throughout the project, DOT officials also worked with local schools and community groups to explain how roundabouts operate, using model vehicles and farm equipment to demonstrate proper traffic movements. Wednesday’s Roundabout Rally will continue that educational effort, giving motorists an opportunity to experience the new intersection firsthand.
The Iowa DOT reminds drivers approaching a roundabout to slow down, yield to traffic already inside the circle and travel counterclockwise until reaching their exit.
