Rock County Inman Parkway Extension (New CTH BT)

« Return to Project Search

Rock County hired Ayres to analyze several alternatives and prepare final plans and specifications for a new connector route between CTH G and CTH S at the north edge of the City of Beloit near the IH 39 interchange. The selected alternative included a 240-foot-long new bridge over Turtle Creek. This selected route also included reconstruction of the CTH G and Inman Parkway intersection and construction of a new roadway corridor. Ayres worked closely with local County, Town, and City officials as well as the public in the project area. The route is designated as an IH 39 alternate route for the interstate expansion project and required significant design and schedule coordination with the Wisconsin Department of Transportation (WisDOT) and adjacent projects on CTH G.

The purpose of this project was to provide a new route that will improve access to IH 39/90 from the north side of the City and from the Towns of Beloit and Turtle. It will reduce congestion along existing routes while also shortening travel times. The roadway is a new 1.4-mile, two-lane county highway with a rural cross section and required new storm sewer and the addition of infiltration trenches to minimize runoff to adjacent properties. Analysis was completed for incorporating either traffic signals or roundabouts at the CTH G intersection, which resulted in a recommendation for installation of new traffic signals.

An environmental assessment document was prepared and required significant agency and local official coordination. Ayres led the way on the public involvement for this high-profile project.

The Turtle Creek bridge was designed to minimize impacts to environmentally sensitive areas along the creek. The new bridge is a three-span prestressed I-girder structure on pile-supported abutments.

Services included preliminary and final roadway plans, environmental document preparation, field survey, stormwater analysis, structure design, traffic analysis, report preparation, agency coordination, and right-of-way plat preparation.

Benjamin Coopman, Rock County’s public works director, said the Ayres project team was quick to identify a potentially problematic design element and an unknown endangered species that needed timely investigation.

Project Information

Client's Name

Rock County Public Works Department


Beloit, WI

Primary Service

Roadway Design


Local Government