Phoenix Metro Area Projects

Loop 303 Improvement Project: North of Interstate 10

Project Timeline


Construction of Loop 303 south, between Interstate 10 to Van Buren Street is anticipated to start in fall 2015 and conclude in late 2017.

Although the initial Loop 303 construction will extend to Van Buren Street, a study is underway for the possible extension of Loop 303 south to the proposed SR 30, with construction anticipated to begin in 2023 and conclude in 2024, per the Regional Transportation Plan.

Other Projects Near Loop 303 / I-10
  • Summer 2015: Loop 303, Thomas to Camelback landscaping
  • Fall 2015: Loop 303 / I-10 Interchange Phase I landscaping
  • 2017*: Loop 303 / I-10 Interchange Phase II landscape design
  • 2018*: Loop 303 / I-10 Interchange Phase II landscaping

*Tentatively programmed


The I-10 frontage roads connecting to/from Cotton Lane opened.


Construction on the segments between Bell Road and Northern Avenue and between Thomas and Camelback roads was completed in late summer. Between Northern Avenue and Bell Road, traffic can use three lanes in each direction at a speed limit of 65 mph. Work also began on the final segment between Camelback Road and Glendale Avenue.


ADOT opened bids for construction of two additional segments in the spring: from Thomas to Camelback roads and from Glendale to Peoria avenues. Construction on both sections is scheduled to begin in the summer. The bid opening for a third section, between Camelback Road and Glendale Avenue, is scheduled for late summer.


In March, construction of the crossroad improvements at Bell, Waddell and Cactus roads was complete. In May, 14 miles of Loop 303 opened between I-17 and Happy Valley Parkway. Construction began on six miles between Mountain View Boulevard and Peoria Avenue in August and on the traffic interchange at I-10 in December.


The federal government approved the Environmental Assessment and issued a Finding of No Significant Impact (FONSI), allowing construction to begin. Work began between I-17 and Happy Valley Parkway. Construction also began on crossroad improvements in anticipation of traffic interchanges at the Loop 303 alignment and Bell, Waddell and Cactus roads.


ADOT published its draft Environmental Assessment for Loop 303 from I-10 to US 60 and held a series of public hearings.


ADOT completed a state-level Environmental Assessment for Loop 303 between Happy Valley Parkway and 43rd Avenue. A federal-level Environmental Assessment also was completed for Loop 303 between 43rd Avenue and I-17.


ADOT reassumed operation and maintenance of Loop 303.


Maricopa County voters approved Proposition 400 to extend the half-cent sales tax for 20 years. The extension would take effect in 2006 and will expire in 2026.


Maricopa County, which was responsible for the operation and maintenance of Loop 303 at that time, completed the first Environmental Assessment and held public scoping meetings.


Maricopa County voters approved a half-cent sales tax through Proposition 300 to fund the MAG Regional Transportation Plan (RTP). The Loop 303 corridor was included in the Voter Pamphlet.


The Maricopa Association of Governments (MAG) identified the need for a West Valley regional connector freeway.