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How Automotive Proving Grounds Work

History of Automotive Proving Grounds
The new Iso Grifo A3 during testing at the Modena Aerautodromo, 1964.
The new Iso Grifo A3 during testing at the Modena Aerautodromo, 1964.
Klemantaski Collection/Getty Images

Until the 1920s, automotive testing was done in the same place as most automobile driving -- on city streets and country roads. But as the automobile became an increasingly important mode of transportation and the roads filled with cars, this ceased to be feasible. It was too dangerous to test cars in public places. Furthermore, auto manufacturers became wary of letting the public see their cars while they were still in the testing phase. Competitors might have a chance to steal trade secrets or journalists might get too close a look at future models.

In 1924, General Motors opened the Milford Proving Grounds in what was then a fairly isolated portion of Michigan. It was the world's first dedicated automotive proving ground. The original site consisted of a gravel loop just under 4 miles (6.4 kilometers) in circumference, plus a straightaway. The entire facility was only 1,125 acres (4.6 square kilometers) in size and only a single employee worked at the proving grounds full time. His name was Ruggles Simcock. He was the maintenance superintendent at the facility.

In 1928, GM printed a pamphlet about the Milford Proving Ground that clearly stated the rationale behind it: "No other industry has gone forward so swiftly with so few basic facts -- facts that are needed if the motor car is to be of increasing usefulness to a greater number of people. If the industry is to continue its rate of progress it must know more facts about the material used, the economics of design and what happens as the car is being operated mile after mile upon the road in the hands of the use. To get these facts, General Motors five years ago decided to establish a proving ground and to make it the most comprehensive undertaking of the kind in the world" [source: GM Heritage Center].

This rationale wasn't lost on other auto manufacturers. In 1925 Ford opened its own proving ground in Dearborn, Mich., and the same year Packard built a proving ground in Shelby Township, Mich. By the mid-1920s, rural Michigan was a hotbed of automotive test tracks.

Now, almost every auto manufacturer has at least one such proving grounds and some have several. Nissan has one in Tochigi Prefecture, Japan. Chrysler has one in Yucca, Ariz., which it purchased in 2007 from the Ford Motor Company, and another in Chelsea, Mich. And what's happened over the years to GM's Milford Proving Grounds? It's grown. It now covers 4,000 acres and has 132 miles (212.4 kilometers) of road. There are multiple tracks, in all shapes from straightaways to loops. There's also a vehicle dynamics testing area (VDTA) known as Black Lake, a 67-acre expanse of blacktop where cars can be driven at top speeds and tested under varying surface conditions. Alas, rural Michigan isn't as rural as it used to be and GM has periodically considered selling the site, which is now surrounded by modern development. Although this would represent the loss of an historic facility, GM can make do without it. The company has additional proving grounds in Arizona, Mexico, Brazil, Australia, England, Brazil and Germany. And there are plenty of independent automotive testing centers that would be happy to pick up the slack.

So what are these testing facilities like? On the next page, we'll take a look at a typical automotive proving ground and talk about what goes on there.