The City of Phoenix retained Olsson to prepare a design concept report and an environmental determination report for this highly visible and complex project in the most prestigious business neighborhood in Phoenix. After providing a preliminary evaluation of alternatives, we recommended the underpass option with an aesthetically enhanced plaza at each entrance. The city then requested that Olsson complete the final design of the recommended alternative.

The entire roadway segment from 24th Street to 26th Street was geometrically revised to design the underpass as a shallow crossing. The vertical profile of Camelback Road was raised by about 6 feet at the underpass location so that it matched the existing grades just east and west of the 24th Street and 26th Street intersections, respectively. The horizontal alignment of the roadway was significantly changed to create an additional plaza area on the southern side of Camelback Road.

The complex structural design incorporated unique architectural and aesthetic features. Drainage design included analyzing off-site contributing runoff using HEC-1 software and storm drain reconstruction to lower the existing storm drain so it could pass under the new pedestrian underpass. Utility relocation (including fiber-optic duct banks) and construction sequencing in one of the busiest sections of Phoenix made the underpass design very challenging. Because of the project’s complexity, Olsson conducted numerous design workshops and public meetings.

The Camelback Road Pedestrian Underpass project has won 13 local and national awards.