When Stanley Consultants was asked to provide full design for five miles of expansion of State Route 24, a controlled access urban principal freeway, engineers planned for both the present and future roadway expansion.
SR-24, as it is known, is a vital link between the southeastern Maricopa and northern Pinal County communities to the Phoenix metropolitan area for more than 150,000 residents. The 5-mile interim expansion, running from Ellsworth Road to Ironwood Drive, will reduce traffic congestion on local streets in the surrounding communities, improving mobility for residents and businesses. It supports existing and predicted traffic demands, improves connectivity and promotes economic development.
The interim expansion was designed to the ultimate freeway configuration, with three general-purpose lanes, one auxiliary and one high-occupancy vehicle (HOV) lane in each direction. Then the design was purposefully scaled back to the interim design with two lanes in each direction until funding becomes available for the ultimate build-out.
Two project objectives were to preserve the ultimate right-of-way and optimize interim elements in ultimate configurations to minimize future asset throwaway – assets such as pavement or drainage features that are later deconstructed. To that end, the designers used what will be future entrance and exit ramps as travel lanes through the intersections. With the completion of the interim roadway, motorists can now access SR-24 at four new interchange locations: Williams Field Road, Signal Butte Road, Meridian Road and Ironwood Drive.
When funds become available, the additional lanes and overpasses to create the ultimate freeway can be seamlessly added with minimal throwaway and inconvenience to drivers.