Work to replace bridges over the Gila River on Interstate 10 south of Phoenix is expected to start this spring as part of a plan to widen 26 miles of often congested freeway.
The stretch of I-10 in question runs just shy of Casa Grande north through the Gila River Indian Community to Loop 202 Santan and South Mountain freeway.
It includes the only two-lane portion of I-10 between Tucson and Phoenix.
Regional, state, federal and tribal governments are working together to pay for the roughly $1 billion project.
Officials say a window for people to comment on the final environmental assessment and design concept is expected to open in April.
Mid-2028 is the current estimated date of completion for the entire widening project.