What happened to the Phoenix Proving Ground near South Mountain?
Only in Arizona: Massive 4,100-square-acre property in Ahwatukee Foothills helped develop trucks and tractors during post-war industrial boom.
Post World War II, Arizona drew many large companies looking to test its cars, tires, aircrafts and heavy equipment in the open space and harsh desert conditions found only in our part of the country.
General Motors, Goodyear, Ford and others maintained operations on the fringes of the Valley in far East Mesa, Litchfield Park and the Northwest Valley.
But one facility operated by the International Harvester Company was much closer to the city center — Phoenix Proving Ground — about seven square miles on the south side of South Mountain in today's Ahwatukee-Foothills area.
“Its main function was to stress test heavy duty equipment and trucks, and tracks were created — both paved and unpaved, as well as specific grades,” said Sally Jacobs, an archivist for the Wisconsin Historical Society and keeper of all things International Harvester. “International Harvester leased the land from the state before purchasing it.”
Running roughshod over 4,100 acres
Framed by South Mountain/Telegraph Pass to the north, Pecos Road to the south, 24th Street to the east and Desert Foothills Parkway to the west, International Harvester ran roughshod over 4,100 acres for about 40 years after the Proving Ground opened in 1947, testing everything from long-haul trucks to earth-movers, and tractors to consumer pickup trucks.
Jacobs shared a treasure trove of historic photos and company documents about the company's state-of-the-art Phoenix facility, which showed the heavy equipment manufacturer logged more than 5.1 million test miles, or 34,000 miles per week around the clock, between February 1948 and October 1951.
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There was a seven and a half mile paved test track on site that included: a 9 percent grade, a four-mile dirt track, special test areas with 20 to 60 percent grade, an airplane runway for company executives, service shops and more. Much of the company's research and products would be used after the passage of the Federal Highway Act of 1956, creating the national highway system.
Closing the proving ground
So what happened to such a vital research facility? Why did International Harvester close up Phoenix Proving Ground?
That story remains somewhat complicated, but a combination of economic woes, including labor union problems and a patent infringement judgement against the company, prompted the 1983 sale of Phoenix Proving Ground to local developer Burns International.
Burns later partnered with the Del Webb Corporation to develop The Foothills and Club West. Much of the new development, including new home and golf course communities, followed the same blueprint established by International Harvester's trucks and tractors.
As an interesting side note, the land to the west of the Phoenix Proving Ground was once slated for a state correctional facility; the state Legislature appropriated $5 million for its construction on 320 acres in 1973, but later scrapped the plan. Perhaps they saw the need for an Interstate-10 bypass in Phoenix's future.
Contact “Only in Arizona” columnist Mark Nothaft at firstname.lastname@example.org. Send him the weird and fun facts and places found #OnlyInArizona.
Arizona still a testing hotbed
Large manufacturers today still come to Arizona for the heat, dust and large expanses to test products. Toyota beats up its Corollas and Camrys outside of Wickenburg, as do Ford and Mazda. Chrysler operates near Kingman, Komatsu heavy equipment moves earth south of Tucson, while General Motors struck a deal with the U.S. Army to share part of Yuma's legendary proving grounds. The automaker likes the site since other companies find it difficult to spy on their prototypes.