A report on the possible economic impacts of a proposed connection between interstates 10 and 19 says the new highway would provide a multibillion-dollar influx into the regional economy.

The Pima County-commissioned report by Phoenix-based Applied Economics estimates a Sonoran Corridor bypass connecting the two interstates south of Tucson International Airport would eventually create a $32.2 billion annual impact to the regional economy.

That assessment comes at a time when Pima County voters have begun to receive election ballots, which include a proposition to put $30 million into construction of the Sonoran Corridor project.

“The timing was just when we got the actual report,” Pima County Administrator Chuck Huckelberry said.

The report was commissioned about a year ago, Huckelberry said. The county paid about $10,000 for the report.

County leaders have proposed construction of a 26-mile connection between I-10 and I-19 as a bypass primarily for northbound I-19 and westbound I-10 drivers, especially commercial vehicles.

The Sonoran Corridor would run roughly from Rita Road on the southeast side to about Pima Mine Road south of Tucson through areas with little existing development.

Huckelberry said bond funding would make up only a small fraction of the total cost of the corridor, which is estimated at more than $600 million.

Recently, Arizona’s entire congressional delegation got behind a measure that helped get the proposed interstate connection listed among Federal Highway Administration planning documents. The listing makes the project eligible for federal funding.

The county’s analysis says the possible business expansion associated with the Sonoran Corridor project among three main employment segments would directly and indirectly support as many 189,000 jobs.

As many as 104,000 people could work directly for tenant companies in the bypass corridor at build-out. Those workers would earn an estimated $5.2 billion, or $50,000 per worker, annually.

Huckelberry said the large figures show the possible impacts many years down the road, assuming the highway project gets completed and businesses relocate to the area.

That’s a lot of assumptions, says Avra Valley resident Albert Lannon.

“It’s based on assumptions, projections and what ifs,” Lannon said. “I think it’s pure speculation.”

He’s been a vocal opponent of the $816 million bond package before voters in November and has opposed plans for interstate expansions, including the proposed Interstate 11 plan through Avra Valley.

Another concern Lannon has is with who would benefit from construction of the Sonoran Corridor.

Real estate investor Don Diamond‘s company — Diamond Ventures — has for many years owned a 3,000-acre section of undeveloped land southeast of the airport.

The company has a master-planned community proposal for the land called Swan Southlands.

Lannon said the proposed highway route would benefit the company.

“Dropping it south looks like a gift to Don Diamond,” he said, noting the highway would run west from Rita Road then drop sharply south before turning west north of Pima Mine Road.

Huckelberry said the proposed alignment was not chosen to benefit any private landowners.

“It’s a location that we’ve worked with the San Xavier district (of the Tohono O’odham Nation) to minimize the impacts,” Huckleberry said.

A straight east-west connection starting at Rita Road would end up running through areas of archaeological significance to the tribe. A similar east-west alignment farther south would run through areas in the southeast known for widespread flooding.

Huckelberry said the development of the Sonoran Corridor as a way to facilitate growth in the aerospace, defense, high-tech and industrial sectors would be an economic milestone for the region on par with Hughes Aircraft and IBM coming to the region and the post-World War II growth of Davis-Monthan Air Force Base.

“This ranks up there with those,” he said.

Huckelberry also said the region, which today is mostly free of residential or other development, represents one of the few areas remaining in the Tucson region that could sustain new large-scale industrial development.

Lannon said he doesn’t think the Sonoran Corridor fits with the interests of the region.

“It sounds more like exporting jobs across the border and jobs from the Port of Long Beach for the Port of Guaymas,” he said. “I don’t think taxpayers should pay billions of dollars to export jobs.”

Contact reporter Patrick McNamara at pmcnamara@tucson.com or 573-4241. On Twitter: @pm929