Garrity Boulevard Interchange Redesign
Dr. George Murgel and Dr. Molly Gribb
Interstate 84 serves as the main corridor through Idaho. It allows for commuters to safely travel from Canyon to Ada County while still providing freight an avenue through the state. In 2001, the Community Planning Association of Southwest Idaho and the Idaho Transportation Department performed an I-84 Corridor Study of the roadway between the Wye Interchange and the city of Caldwell. The results suggested a need for roadway expansion between the Meridian Interchange and the Garrity Interchange in order to accommodate for the increased traffic densities on this stretch of roadway. The scope of this project required all of these designs to be executed so as to sufficiently service both I-84 and Garrity Boulevard through the year 2030. In this senior design project, all four aspects of civil engineering were examined: transportation, structural, geotechnical, and environmental. For the transportation aspect, the existing on-ramps and off-ramps were evaluated and the west bound on-ramp was redesigned as necessary to account for a new level of service E. The Garrity Bridge was widened to accommodate for four lanes of traffic in each direction instead of the current two. In conjunction to the bridge widening, the existing retaining walls were redesigned to fulfill the structural component. In both of these cases, the soil foundations were analyzed to satisfy the geotechnical element. Lastly, for the environmental analysis, a storm water drainage plan was completed. These improvements will both increase safety and increase efficiency of the Garrity Boulevard Interchange.