US 20 at Harmony Road Intersection Improvements

CLIENT: Illinois Department of Transportation (IDOT)

At the rural intersection of US 20 and Harmony Road in McHenry County, IDOT sought improvements to address a history of crashes. Clark Dietz led a Phase I preliminary engineering and environmental study to evaluate a traffic signal and a modern roundabout. The roundabout was selected as the preferred alternative.

The study examined existing and proposed drainage conditions, easements and right-of-way needs, and traffic control during construction. Clark Dietz also completed two Intersection Design Studies, a Project Report, and a Drainage Technical Memorandum.

To help the public understand the options, Clark Dietz facilitated an informational meeting with an introductory presentation and six workstations. Visitors could explore roundabout design, traffic capacity and delays, safety, access for trucks and emergency vehicles, pedestrian travel, and public and business perspectives. The team also prepared a project website, brochures, announcements, exhibits, and 3D visualizations of both alternatives.

Through engineering analysis and public involvement, the study gave IDOT a preferred alternative for improving safety at the intersection.