State transportation officials are moving into the next phase of a project once seen as a stopgap for State Route 347 congestion — and they’re asking the public to weigh in.

The proposed Koli Road traffic interchange, located between the Wild Horse Pass Boulevard and State Route 347 exits on Interstate 10, aims to reduce congestion and improve access to the rapidly expanding corridor. That includes tens of thousands of drivers from Maricopa who use the corridor daily to reach jobs and services in the Valley — or detour around backups at the top of SR 347.

Koli Road is currently a 2½-mile desert road serving equestrian areas near Firebird Motorsports Park. But under the Arizona Department of Transportation’s proposal, it could become a critical connector, offering drivers another way out when crashes or bottlenecks snarl the already overburdened SR 347.

On Tuesday, a four-car crash shut down the northbound lanes of SR 347, bringing traffic to a standstill for more than half the workday and disrupting the commute for its 50,000 daily drivers. A story about the traffic nightmare quickly became the top trending article on InMaricopa.com, with more than 17,500 readers. That day, many drivers were forced to detour to I-10.

The new interstate exit “would be an additional traffic interchange that would alleviate traffic from” Loop 202 and SR 347, said Joanna Bradley, assistant director of communication over major projects for ADOT. “If there was a traffic impact, if there was a crash, it would just be another interchange that would help alleviate traffic in general.”

A virtual public hearing is scheduled for July 30 from 5:30 to 7 p.m., where ADOT will present findings from the environmental assessment and design memo, outline its preliminary recommendation and collect public comments.

Full meeting details are available here.

Maricopa dominated the public comments

The public comment period, which ended in November, drew 129 responses — and Maricopa’s role was front and center. According to ADOT’s summary:

• Some questioned whether the Koli Road interchange would help SR 347 at all, saying it might have “no impact or negative impact” on corridor safety and flow.

• Others worried it could siphon funding away from SR 347 projects — concerns raised before the SR 347 widening was officially funded and confirmed.

• With SR 347 now set for widening between Maricopa and I-10 starting in 2027, fears about funding may be easing while concerns about impact are worsening.

ADOT is evaluating three alternatives: a traditional diamond interchange, a diverging diamond interchange known as a DDI or a no-build option that maintains the status quo.

In an InMaricopa.com poll of 584 commuters in October, the diverging diamond interchange led with 38%, followed by 36% in favor of no build and 26% for the diamond interchange.

ADOT previously said the diamond interchange scored best overall in environmental and performance assessments, offering the most benefits with the least impact. However, ADOT now recommends the DDI.

The study area spans roughly a half mile east and west of I-10, from Maricopa Road to the east and extending just past Wild Horse Pass. It also extends in 1.7 miles to the southwest “to encompass the existing Maricopa Road, where the Koli Road Extensions would tie into,” said Marcy McMacken, a public information officer for ADOT.

The environmental assessment has reviewed potential impacts on cultural sites, water quality, biological resources, noise, air quality, recreational areas, land use and farmland.

Both build options would require land acquisition — 36 acres for the DDI and 34 acres for the diamond interchange, with nearly all of that from Gila River Indian Community lands or allotted parcels. According to ADOT’s Carmelo Acevedo, the DDI would cost more in construction and right-of-way acquisition than the more familiar diamond layout.

“Arizona currently has over 400 diamond interchanges in operation, compared to just four full DDIs and two half DDIs,” Acevedo said. “The diamond interchange provides the highest rating in the criteria assessed and meets the purpose and need.”

A final design is expected to be chosen by the end of the year.

What happens next?

Maricopa commuters often use Wild Horse Pass Boulevard as a detour when SR 347 backs up. But with major, long-term roadwork planned for that highway, it’s harder to say how useful a new I-10 exit toward SR 347 would really be — especially since most public feedback focused on Maricopa.

Even so, ADOT recommends moving forward. Officials said they would announce a decision on the preferred alternative in “late 2025.”

The proposed interchange is part of the Wild Horse Pass Corridor Projects and is being developed in partnership with the Gila River Indian Community, the Bureau of Indian Affairs, the Federal Highway Administration and the Maricopa Association of Governments.

MAG has allocated $117 million for right-of-way acquisition, design and construction — with $83 million for construction and $30 million for land and utility work.

GRIC would fully fund local road extensions connecting Koli Road to the new interchange.

After the July 30 meeting, ADOT will review public comments, complete an environmental review and ultimately begin construction.