Currently, the left turn movement for southbound traffic on K-113 to the on-ramp for eastbound K-18 experiences significant congestion during the peak traffic conditions. The City of Manhattan and Kansas Department of Transportation are pursuing improvements to increase capacity and improve traffic operations. Citizen input, traffic data and design analysis was completed as part of the project and was utilized in a value planning workshop that resulted in a recommended alternative that provides the best solution for existing and future conditions.
An array of alternatives were evaluated for performance, public acceptance, and cost. A comprehensive traffic study was completed that included the interchange and intersection of K-18 and Rosencutter. A Value Planning Workshop was held with City and KDOT staff. Alternatives considered included a loop ramp, roundabouts, diverging diamond and dual left-turn lanes. Benesch’s study ultimately recommended a diverging diamond intersection (DDI) that included traffic signals, street lighting and ITS elements.
Additional traffic analysis was completed for the Diverging Diamond Alternative. VISSIM was used to analyze the DDI geometrics to confirm the number of lanes required to handle the 20-Year traffic volumes.