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  • Location: Phoenix, Arizona

Southern Avenue, between 51st Avenue and 37th Lane, is an arterial roadway that is maintained jointly by the City of Phoenix and the Maricopa Department of Transportation (MCDOT). Southern Avenue facilitates access to several popular destinations including the Maurice C. Cash Elementary School, Rogers Ranch School, the American Legion, SR-202L South Mountain Freeway and the future SR 30 Tres Rios Freeway. While the roadway varies from a 2-lane roadway to a 4-lane roadway, there are multiple pinch points within the 1.7-mile segment resulting in existing traffic demands to push the corridor over the acceptable service load.

Additionally, Southern Avenue serves as a transit corridor, yet it lacks pedestrian accommodations such as sidewalks, striped crosswalks near bus stops and proper lighting. This leads to dangerous pedestrian/vehicle conflicts and creates many safety concerns. B&N was contracted by MCDOT to lead the scoping and design improvements for the corridor while addressing safety and capacity concerns.

Because the project spans the City of Phoenix and unincorporated Maricopa County, it also presents the unique challenge of working across multiple jurisdictions and stakeholders which could result in roadway design, maintenance, funding and project management conflicts between owners.

Intergovernmental Agreement

In 2018, multiple fatal crashes highlighted the issues along the corridor. City and County agencies quickly responded by partnering to study the issues and implement solutions. Intergovernmental agreements (IGAs) between MCDOT and the City of Phoenix were established to address funding contributions, project roles and maintenance responsibilities. To streamline facility maintenance, the City agreed to enter an IGA with MCDOT to annex the roadway in its entirety upon the completion of construction. This required close coordination between MCDOT, Phoenix and B&N to ensure the success of the project.

Working together with stakeholders and project owners, B&N completed the project in seven months – five months shorter than a typical project of this scale. In that time span, B&N examined existing conditions, engaged the community, developed and evaluated alternatives, recommended a solution and facilitated the initial IGA process. Overall corridor improvements included installation of pedestrian related safety improvements, a raised median, drainage system, roadway lighting, bus bays and traffic signal upgrades. Pedestrian related safety improvements included HAWK Beacons, closing sidewalk gaps and ADA compliant curb ramps.