I-17 Improvement Project
I-17 Improvement Project
Contents
Overview
The I-17 Improvement Project covered a 23-mile section of Interstate 17 between Anthem Way and Sunset Point. Construction began in September 2022 and was completed in December 2025. This I-17 corridor north of the Phoenix metropolitan area sees more than one million travelers annually, making it one of the most heavily traveled roadways in Arizona.
Project Corridor
The goals of the I-17 Improvement Project were to add capacity, reduce congestion, improve traffic flow and enhance safety, while also supporting travel, tourism and economic development. The major components of the project included:
- Adding a third travel lane in both directions along the 15 miles between Anthem Way and Black Canyon City
- Constructing two new flex lanes along the 8 miles between Black Canyon City and Sunset Point
- Widening 10 bridges and replacing two others
During construction, nearly all of the material removed during controlled rock blasting and major earthwork operations was reused and put back into the project. Rock material was crushed and used for paving, aggregate base, bridge abutment protection, embankment, rip-rap and rock mulch. This project was delivered as a Public-Private Partnership (P3) and Design-Build-Operate-Maintain (DBOM).
This project was delivered as a Public-Private Partnership (P3) and Design-Build-Operate-Maintain (DBOM).
Flex Lanes
The flex lanes are the first of their kind in Arizona and were constructed through the mountainous area between Black Canyon City and Sunset Point. The lanes serve as an additional two-lane roadway that carries one direction of traffic at a time and can alternate between north- and southbound directions, depending on the greatest need.
The flex lanes run adjacent to the two southbound general purpose lanes and are typically open to northbound traffic Mondays through Saturdays, then transition to southbound traffic on Sundays. For more information, check out our flex lanes fact sheet.
