Arizona Gov. Doug Ducey has signed legislation earmarking $400 million in state general fund cash to add a third lane in each direction to a section of Interstate 10 south of Phoenix.
The 26-mile stretch is the last section of I-10 between Phoenix and Tucson that is still just two lanes and has long been a congested bottleneck.
That has led to slowdowns between Chandler and Casa Grande that limits commerce and impacts commuters traveling the section to and from growing Pinal County.
Ducey said at a Wednesday signing ceremony that new manufacturers in Pinal County need the expansion, as do companies hauling freight from Mexico, commuters and tourists.