The lawsuit suggests that because the ballot measure only received 59.82% of the vote, it should not become law because the Arizona voters in 2022 amended the state’s constitution to require tax proposals to reach a 60% threshold. 

Proposition 479 asked Maricopa County voters to continue a half-cent sales tax for the next 20 years. The tax was first approved by voters in 1985 and again in 2004. This tax provides revenue for the regional transportation plan approved by mayors across the county, accounting for $14.9 billion, or half, of the $28.2 billion plan. 

Bryan Blehm, an attorney for the group, argued that the referendum should be decertified because it fell short. He believes this referendum was a new tax, not an old tax, which would require it to reach the 60% threshold.

Connect Maricopa, the campaign committee supporting the transportation initiative, filed a motion to intervene Wednesday. On Thursday, the county asked the courts to dismiss the lawsuit entirely.

Phoenix Mayor Kate Gallego, a Democrat, called the lawsuit “deeply flawed.” 

“Maricopa County voters overwhelmingly passed Prop. 479 because they understand that a strong transportation system isn’t political,” she said. “It’s critical to our future. This lawsuit is deeply flawed and misguided, and I hope the courts recognize its malignant intentions.”

In the breakdown of the measure, 40.5% of the tax revenue is set to fund freeways, 33.5% would fund bus transit and bus rapid transit, 22.5% would go to major roadways and regional transportation infrastructure, and 3.5% would go to light rail maintenance. 

Gov. Katie Hobbs (D-AZ) released a statement on the lawsuit, saying the proposition will “help create hundreds of thousands of jobs, attract billions of dollars in investment, and continue driving Arizona’s economic momentum forward.”