US-75 and 46th Street Interchange
Shawnee County, Kansas 2005 KS ACEC Transportation Engineering Excellence Award

Wilson & Company was retained to design an interchange to replace the existing at grade intersection located on US-75 at 46th Street north of Topeka, Kansas. The area surrounding the interchange site was fully developed in three quadrants including a church, residential development, and a convenience store. A strip mall and residential development was under construction in the fourth quadrant. Initially, Wilson & Company completed a concept study to evaluate alternative interchange layouts. The study consisted of development of several interchange concepts, traffic analysis, preliminary right-of-way requirements, and preliminary cost estimates. The team evaluated a diamond, a tight diamond, a parclo, and a single point urban. Based on exhaustive analysis, all of the above options were found to be unacceptable. Wilson & Company then turned to new and innovative designs. We evaluated several roundabout configurations. As a result, the single roundabout option was selected as the best alternative. This design provides the capacity for the horizon year traffic while minimizing the impacts to surrounding development. Additional details about innovative structural aspects of the project. Client Contact: Jim Richardson Road Design Leader Kansas Department of Transportation 13th Floor, Harrison Center 700 SW Harrison Street Topeka, KS 66603-3754 Construction Cost: $12.6 Million Completion Date: 2003