Proposition 479 is Underway

20 More Years of Transportation Investment Celebrated with Groundbreaking

On Friday, March 6, Proposition 479, the future of transportation in the region, was celebrated by state and local officials, the business community, and transportation infrastructure partners.

Prop 479 is the continuation of an existing, dedicated half-cent sales tax in Maricopa County to fund transportation. The half-cent sales tax was first established by voters in 1985, with the approval of Proposition 300, and subsequently renewed in 2004, with Proposition 400. Voters approved Prop 479 on November 5, 2024, extending the tax until 2045.

The groundbreaking event took place on the site of the first major project of Proposition 479: the Loop 303 and I-17 system interchange. With the official groundbreaking ceremony, work on the interchange is underway and expected to take 2.5 years to complete.

Key Numbers:

Under Proposition 479, future planned improvements over the next 20 years include:

• 331 new freeway/highway lane miles

• 134 new HOV lane miles

• 1,000 new or improved arterial lane miles

• Expanded and improved bus service across the region

  
  

Why It Is Important:

“Regional support for the half-cent sales tax for transportation helped create the freeway system we enjoy today,” said El Mirage Mayor Alexis Hermosillo, MAG Regional Council chair. “This support has paved the way for infrastructure investments through propositions 300, 400 and now 479, all of which have kept the region moving forward, realizing a more prosperous future for generations to come.”

“Over the next 20 years, the projects approved under Prop 479 are projected to reduce afternoon commute times by as much as one third,” said Glendale Mayor Jerry P. Weiers, Transportation Policy Committee chair. “Prop 479 is also projected to save local businesses $1.6 billion every year in travel time, shipping, and logistics costs – and support more than 31,000 good-paying jobs.” 

Maricopa County residents will be able to identify what projects their investment in regional transportation are paying for by the bright orange ‘Prop 479 At Work – Moving Us Forward’ signs that will be present near construction zones.

Groundbreaking Event Highlights:

• Arizona Governor Katie Hobbs emphasized that the Loop 303 and I-17 system interchange groundbreaking marks the first project under Proposition 479 and highlighted how voter-approved transportation investments strengthen Arizona’s economy, support job growth, and keep the state competitive for the future.

• El Mirage Mayor and MAG Regional Council Chair Alexis Hermosillo framed the groundbreaking as the official launch of Proposition 479, highlighting MAG’s decades-long legacy of regional collaboration and the shared responsibility to deliver transportation investments that improve safety, mobility, and economic opportunity across Maricopa County.

• Phoenix Mayor Kate Gallego stated that voter approval of Proposition 479 reflects the region’s commitment to long-term planning and strategic transportation investments that support economic growth, such as TSMC and the city’s Innovation Core.

• Glendale Mayor and Transportation Policy Committee Chair Jerry Weiers highlighted how Proposition 479 and the Loop 303/I-17 project will improve mobility in the fast-growing Northwest Valley, strengthen a key economic corridor, and demonstrates the power of regional cooperation and collaboration with the state to keep Maricopa County moving.

• ADOT Director Jennifer Toth emceed the event and celebrated the start of the next 20 years of transportation investment in Maricopa County.