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There are currently 10 different proposed routes for The Sonoran Corridor, which would link Interstates 10 and 19 south of Tucson. 

With seating for 120 and most chairs occupied, the Sonoran Corridor study moved forward with another public hearing earlier this month—generally informative in nature, albeit a bit contentious at times.

Attendee attire, from suits and ties to shorts and sandals, spoke to the disparity of the interested parties curious about the proposed Arizona Department of Transportation and Federal Highway Administration’s ‘optimized corridors’ linking Interstate 10 and Interstate 19 on the city’s south side.

The government officials working on this project call it “a regional economic catalyst,” noting that hooking up the two interstates near Tucson International Airport would be a “multilevel, multistep, multiyear economic development initiative” for Pima County and Southern Arizona.

A report on the project suggests that the new travel route ultimately chosen would significantly transform the regional economy, “adding billions of dollars (their estimated annual impact would be $32 billion) and tens of thousands of jobs (their estimate is 200,000 jobs) to the Tucson valley.”

According to the Arizona Department of Transportation, The Sonoran Corridor has been designated a high-priority under the federal Fixing America’s Surface Transportation [FAST] Act that would connect the economy of Southern Arizona and the entire state, relieving congestion at the current I-10/I-19 interchange southwest of downtown Tucson and reducing travel distances south of Tucson.”

Describing the 50-square-mile area surrounding the airport as “a unique nexus of rail, highway, and air transportation infrastructure desirable for a whole host of industries,” ADOT officials say such a project, even if it receives approval at all junctures along the way, would be a long time coming.

Things got started in May 2017 when ADOT, in coordination with the Federal Highway Administration, issued a Notice of Intent to start an environmental review process for such an effort.  The Tier 1 Environmental Impact Statement, which could take up to 36 months to complete, is a required part of such efforts to comply with the National Environmental Policy Act.

During its initial gatherings of public input in June 2017, ADOT emphasized: “No funding has been identified for it, no route has been selected, and there is no timetable for building the Corridor.”

Nonetheless, the next step in the Tier 1 process (which leads to a Tier 2 phase of more detailed environmental and engineering studies examining each segment of projects—and also includes a ‘no-build’ option) took place on Sept. 26 in the latest public hearing.  Joanna Bradley of the ADOT Planning Division opened the meeting by telling the audience that the proposed Sonoran Corridor was Congressionally designated as a “high-priority, high-capacity” roadway. 

Study project coordinator Carlos Lopez handled podium duties at the hearing, the mid-point of the three-year process of winnowing down suggested routes from the initial 32 possible link-ups to the current 10, and subsequently reducing that number further before final alternatives are made public next January—to be followed by even more public hearings on the recommended routes.

Lopez’s series of Power Point slides showed ADOT projections that frequently look 20 or more years ahead profiling the population of the areas in question as growing from one million to 1.4 million in the coming decades, with current area employment of 400,000 increasing to 600,000, advances that will necessitate  additional travel routes to get folks from Point A to Point B easier and faster.

“We’re seeking public input on the routes, connections and options to handle anticipated area growth, mobility, highway system linkages, economic development, environment, and constructability,” Lopez said.  “And before we get to the point of identifying specific potential solutions, we have to have a good understanding of needs, capturing the main themes from the public’s perspective, and utilizing that to help us pare down recommendations for the final round focus next January.”

ADOT Public Information Officer Tom Herrmann narrowed it down a bit further.  

“We’re in the middle of our three-year study to look at the area, both the physical and economic environment, and try to narrow down a 2,000-foot-wide corridor that would make sense…or not…to build a corridor,” he said. “We’re here to listen to what the community thinks.  We really want to hear what people have to say so that when we do narrow the plans down to build a final 400-foot-wide corridor…assuming we do build one…it suits the needs of the community for those who live and work in its proximity.  Funding and construction plans are way down the line.  Right now we’re focused on whether or not the corridor makes sense, what the community thinks about it, and which alternative might be preferred.”

Although the devil is in the details, there are 10 current Optimized Corridors running back and forth from Interstate 19 to Interstate 10 and overlaid one on top of another, they resemble a bowl full of spaghetti.  Taken separately, the options and connections run from I-19 terminus loci near El Toro Road, Pima Mine Road, or the San Xavier District connecting to I-10 terminus sites at Rita Road, Houghton Road, the Fairgrounds or Wentworth Road.

ADOT planners are asking the local citizenry to “help shape the future of transportation in Southern Arizona” by providing public comment by October 26.  

Details and graphics are available at the study website,, via e-mail to or mail to the Tier 1 EIS Study Team, 1221 S. Second Ave., Tucson 85713.