AVONDALE - Opposition is continuing to mount in the southwest Valley against a proposed freeway corridor slicing through Tolleson that Avondale officials claim would cost them millions of dollars in tax revenues.

The Avondale City Council on Monday unanimously adopted a resolution opposing any effort to put the proposed South Mountain Freeway along 99th Avenue south of Interstate 10. That route is one of several being studied by Arizona Department of Transportation consultants as an extension of the Loop 101 around South Mountain and through the Ahwatukee Foothills area.

"We want to send a very clear message to ADOT and the Federal Highway Administration that any alignment on top of 99th Avenue is unacceptable," said Jeff Fairman, Avondale's economic-development director. "There has been some confusion over exactly where the city stands on this alignment. I want to make it clear that it is unacceptable."

Fairman told the council that some developers have already delayed or backed away from projects in the area, simply because ADOT was considering a route there.

Tolleson officials have already adopted a resolution opposing the 99th Avenue alignment and favoring a route along roughly 55th Avenue in Phoenix. That route has long been shown on ADOT freeway planning maps, although it has never been officially designated as the future freeway corridor.

Tolleson officials, who have already hired attorneys to help with their opposition to the route, said putting the freeway along either 99th or 97th avenues would devastate the 6-square-mile city.

ADOT and its consultants are studying possible routes for the freeway along 99th, 97th, 77th, 59th and 55th avenues. The freeway isn't planned for actual construction for at least another seven years, and possibly longer.

"The community's position will be taken into consideration as we move along with the study," ADOT spokesman Doug Nintzel said Tuesday. "The study still has a ways to go."

Avondale officials sent ADOT a study earlier this year estimating that a 99th Avenue alignment could wipe out roughly $500 million in taxable sales generated at the Avondale AutoMall, which is just south of Interstate 10 at 99th Avenue. The report added that a "national client" is in escrow on property in the area in hopes of opening a transportation-related business that would employ 100 people and generate $35 million in annual sales.

Reach the reporter at marty .sauerzopf@arizonarepublic.com or (602) 444-6920.