Marcus, Iowa (SLR) — Construction is now underway on what will become Cherokee County’s first modern roundabout, a major safety project at the intersection of Iowa Highway 3 and Iowa Highway 143 just south of Marcus.
The Iowa Department of Transportation says the redesign is aimed at reducing the number of severe and fatal crashes that have occurred at the rural four‑leg intersection over several decades.
DOT Planner Sarah Tracy says the location has seen multiple serious collisions, including fatal crashes, and that roundabouts have proven to dramatically cut those risks. National and state data show roundabouts can reduce severe and fatal crashes by 70% to 80%, largely by eliminating the high-speed, right‑angle impacts common at two‑way stops. Tracy says that safety, not traffic capacity, is the driving force behind the project.
Work began in early April and will continue through the summer and into late 2026. While the project will require detours at certain stages, the DOT says Highway 3 will remain open for most of the construction period. Drivers can expect shifting traffic patterns and temporary closures on nearby county roads — including L36, C38, and L40 — as crews move into the later phases.
The roundabout will be one of the largest in Iowa, designed with a wider diameter to accommodate farm equipment, semis, and other large vehicles that frequently use the corridor.
Tracy says the DOT has been working to educate drivers — including students in Marcus — on how to navigate roundabouts safely, using demonstrations with model vehicles and farm machinery to show how traffic flows and who has the right of way.
The project has been in development since 2025, when DOT officials first approached the Marcus City Council about addressing safety concerns at the intersection. Local officials say they were not given detailed construction plans ahead of the start date, but the DOT says that the project is moving forward on schedule and that public outreach will continue as work progresses.
KIWA Staff Photo
