First Prop 479 project breaks ground near TSMC

Arizona elected officials and the Maricopa Association of Governments (MAG) broke ground Friday morning on the new system interchange at I-17 and Loop 303, just southeast of the TSMC semiconductor manufacturing complex. This is the first project under Prop 479, which was approved by Maricopa County voters in the 2024 general election, with nearly 60% in favor of the measure.

Prop 479 extends the dedicated half-cent sales tax for another 20 years to help fund regional transportation projects. Replacing the expired Prop 400, it will generate an estimated $14.9 billion to $27.2 billion for freeway expansions, arterial street improvements and public transit, according to MAG.

Planned improvements include:

331 new freeway/highway lane miles

134 new HOV lane miles

1,000 new or improved arterial lane miles

More than 28 miles of Bus Rapid Transit

DEEPER DIVE: What Prop 479’s passage means for the Valley’s future

The groundbreaking is more than just beginning construction on the system interchange, says Arizona Department of Transportation Director Jennifer Toth. It’s about building momentum to deliver on promises made to voters and to work together to support economic opportunity.

“It’s a showcase for our entire region that the innovation corridor is starting off Prop 479, and it shows how closely transportation infrastructure is tied to economic development,” says Phoenix Mayor Kate Gallego.

Within the “innovation corridor,” the new system change will help residents in the area by minimizing traffic, improving road safety and strengthening connections so commuters can have the option to live wherever they want and work wherever they like.

“This Prop 479 was critically important to Maricopa County, but also for the economic future of our state,” explains Governor Katie Hobbs at the groundbreaking. “TSMC is right behind us, and this transportation corridor is incredibly important to continuing to build the economic future of our state and for other regions – not having to compete with Maricopa County for really limited transportation infrastructure dollars.”

Besides economic development and improved infrastructure, this project is also important internationally, by connecting the semiconductor industry with the Valley and the rest of the U.S.

“When this work is complete, it will improve travel, reduce congestion and enhance safety for the thousands of people who use these corridors every day,” says El Mirage Mayor Alexis Hermosillo, who chairs the MAG Regional Council. “Just as importantly, it will help ensure this region remains connected, competitive and prepared for continued growth.”