History and Purpose - Black Canyon Cross Roads

Interstate 17 (Black Canyon Freeway) is a major transportation route through Arizona, Maricopa County and within the metropolitan Phoenix area. It first opened as State Route 69 in 1957. Much of the I-17 corridor was completed in the 1970s and 1980s with no major upgrades, even as metropolitan Phoenix has grown rapidly. I-17 is critical to the effective and reliable movement of people, goods and services throughout the region. Because I-17 is so heavily traveled, it acts as the backbone, or “spine,” of the regional transportation system.

The Spine Study

In 2017 the Maricopa Association of Governments (MAG), the Federal Highway Administration and ADOT completed a study to develop a Corridor Master Plan for the I-17. Known as “The Spine Study,” it analyzed long-term strategies to improve mobility. The study evaluated the full range of transportation modes and concepts to identify the best multimodal solutions. These long-term solutions were viewed as a combination of traditional methods, new technology and increased use of transit.

The study also noted that statistically there is a greater amount of traffic that travels over the I-17 in an east/west direction versus traffic on the I-17 in a north/south direction, and that poor operation at I-17 and the cross roads adversely affect local streets.