48th & State Roundabout Study, Quincy, Illinois
Poepping, Stone, Bach & Associates completed a Feasibility Study and Intersection Design Study (IDS) of traffic control options for the proposed intersection improvement at 48th Street and State Street in Quincy, IL.
The feasibility study compared two alternatives for the improvement of operations and safety of the subject intersection. Specifically, the installation of traffic control signals versus construction of a roundabout. Existing traffic data was collected, and accidents for the last five years were provided by the Adams County Highway Department and the City of Quincy. Capacity analyses were performed for both alternatives for comparison of their operation effectiveness, and each alternative was analyzed as a potential countermeasure for the accident types recorded for their effectiveness on safety. Estimated construction costs were compared and an alternative was selected.
PSBA recommended the roundabout alternative for improvement. The Final Intersection Design Study was approved by the Illinois Department of Transportation.