Newsroom | Easing Traffic Headaches on I-10

MAG News

State Route 30 could provide relief to one of the most congested freeways in the region.

State Route 30 could provide relief to one of the most congested freeways in the region

Prop 400, Prop 479

The photo above shows the current South Mountain (Loop 202) Freeway. The Center Segment of the proposed SR 30 would connect with Loop 202 then continue west roughly four miles south of the I-10.

Thousands of cars and trucks travel on I-10 through the West Valley every day. At peak times, the lines of traffic can stretch for miles. With more distribution centers and warehouses springing up along the Loop 303 corridor, traffic on I-10 west of downtown Phoenix is only projected to increase. But a freeway planned since the early 2000s seeks to help relieve traffic congestion.

SR 30 Essential to Solving Traffic Problems

SR30 SignState Route 30, also known as the Tres Rios Freeway, is a proposed east-west freeway that would connect the West Valley cities of Buckeye, Goodyear, Avondale, and Phoenix. Sitting about four miles south of I-10, the future corridor, along with Loop 202, would provide an alternative travel corridor around downtown Phoenix, providing much-needed relief for everyone who lives and works in the area.

As more and more businesses move their distribution networks to the West Valley and the Loop 303 corridor, having an alternative route to ease some of the traffic congestion on I-10 is essential.
Avondale Mayor Kenn Weise, former MAG Chair

Kenn WeiseAvondale Mayor

“The SR 30 is vitally important for continued growth in the southwest portion of the region,” said Avondale Mayor Kenn Weise, former MAG Chair. “And, as more and more businesses move their distribution networks to the West Valley, having an alternative route to move those goods and services, as well as ease some of the traffic congestion on I-10, will be essential.”

Maricopa County is the nation’s fastest-growing county, and that growth is stressing the region’s transportation infrastructure. As the designated metropolitan planning organization, MAG is responsible for identifying, planning, and funding the large and sophisticated multimodal transportation projects that help keep the Valley on the move. But delivering large construction projects, such as SR 30, can take decades.

Traffic on Broadway Road near South Mountain Freeway entrance.

Traffic on Broadway Road near the South Mountain Freeway entrance.

Prioritizing Congestion Relief, Improving Daily Commutes

The proposed SR 30 consists of three segments: the West Segment, from SR 85 to Loop 303; the Center Segment, from Loop 303 to Loop 202; and the East Segment, from Loop 202 to I-17. Funding to construct portions of all three sections is identified as part of Proposition 479, an extension of the dedicated half-cent sales tax for transportation that will go before Maricopa County voters in November 2024.

SR 30 (Tres Rios Freeway) Map: SR 85 to I-17

In terms of priority, the Center Segment would have the greatest and most immediate impact on congestion on I-10, providing critical regional connectivity improvements that address the highest levels of demand.

Efforts are underway to make sure there is a seamless transition from planning to construction of the Center Segment upon voter approval of Proposition 479. More than $500 million has already been allocated to advanced right of way acquisition and utility work for this segment under the current Proposition 400. Efforts to start the final design also are underway.

Planned Implementation of State Route 30

All three segments of SR 30 are at different stages of the planning and development process. The Center Segment is planned as a six-lane facility between Loop 202 and Loop 303. This segment would include full system interchanges at both ends of SR 30 with Loop 202 and Loop 303.

In 2021, a scoping study was completed for the East Segment to identify the recommended corridor. The East Segment of SR 30 is also planned to be a six-lane facility connecting I-17 and Loop 202. Scoping and environmental work to determine the preferred alignment would begin after voter approval of Proposition 479.

The West Segment will run from Loop 303 to SR 85. Funding has been identified as part of Proposition 479 to construct interim freeway improvements in the corridor, which will then be upgraded to the facility’s ultimate configuration in the future. For this segment, funding has been allocated in the first phase of Proposition 479 to advance initial scoping and environmental work.

Impacts of Project Delays

Former Governor Doug Ducey’s veto of HB 2685, which would have allowed a vote on a tax extension in 2022, caused setbacks to the original implementation plan for SR 30. It is estimated that the implementation of the Center Segment was delayed by two years, resulting in more than $300 million in inflationary costs to the project. Further delays will lead to more significant cost increases.

An economic impact analysis conducted by MAG estimated that delaying the Center Segment by five years would result in 32 million additional passenger hours spent in congestion for vehicles traveling on I-10, resulting in more than $830 million expended on travel costs.

Legislation to enable the vote to extend the region’s dedicated half-cent sales tax, Proposition 479, was ultimately passed during the 2023 Legislative session. It was signed into law by Governor Katie Hobbs on August 1, 2023. This has allowed planning efforts on the SR 30 corridor to again move forward.

Complex and Crucial Corridor

SR 30 is a complex corridor to deliver. It has required some of the most significant advanced planning efforts to date for a freeway project in the region. At the same time, SR 30 is also one of the most needed freeways in the Valley to provide relief to one of the key commercial corridors, Interstate 10, which is the only east-west, cross-country connection for southern Arizona.

Published December 20, 2023