Lemmon Drive Diverging Diamond Interchange

The Lemmon Drive Segment 1 and Diverging Diamond Interchange Project improves safety and provides additional capacity by widening Lemmon Drive from four to six lanes between Sky Vista Parkway/Buck Drive and Military Road. Multi-modal safety and connectivity were greatly enhanced by adding dedicated bicycle lanes and a separated multi-use path. A continuous raised median eliminates hazardous left turn movements across opposing traffic. To accommodate business egress movements, a dedicated U-Turn area provides safe access management. Located within the closed basin system of Swan Lake, water quality improvements included both a retention basin and a detention basin. Aesthetic features included a rock patterned formliner along the retaining wall, and specialty fence and enhanced driveway grading access for a local animal boarding facility.

Reconfiguration of the US 395 / Lemmon Drive interchange to a Diverging Diamond interchange was added to the project during the 90% design phase to better synchronize the Segment 1 widening improvements with the proposed US 395 North Valleys Project Freeway improvements that will add merging lanes between the interchanges.

The DDI has several safety and operational benefits. There are fewer conflict points and only two traffic signal phases are required, adding the benefit of increased left turn lane storage without needing more lanes. The DDI also provides several cost benefits: the existing bridge structure can be used and no additional right of way is required. During construction, the closure of the southbound exit ramp and eastbound movements through the interchange allowed expedited construction, with completion in only 3 months. Safety improvements at the DDI included dedicated bicycle lanes and a protected pedestrian pathway.