Freshened Passat put to test at VW’s secret desert proving ground

Yet, for holding such an important role in the automaker’s development process, the proving ground is all but anonymous. Local residents see plenty of camouflaged vehicles on the roads, but even if they follow them, they’re unlikely to know what lies beyond the hedges.

“We still don’t have a sign in front of the building, and I’m not allowed to fly a Volkswagen flag or any other brand flag in front of the building because we’re still considered a secret prototype facility,” Marsella said.

VW engineers bring the products they’re in charge of to the proving ground for testing and stay to conduct their own tests, Marsella said. During the high-heat season — roughly from April through October — as many as 2,000 engineers from across the global corporate spectrum will visit the Arizona Proving Grounds to conduct their own testing.

Beginning in 2019, the facility will take on another challenge: validating the first of 30 to 50 electric vehicles the automaker plans to introduce by 2025 across its many brands. Work will start here after the first of the year on a 50-vehicle charging facility to help test EVs.

“We will increase dramatically in 2019 the testing of these vehicles,” Marsella explained. “It’s a critical function to test the vehicle in high ambient temperatures, especially now that we’re talking about charge rates up to 350 kilowatts on some of our vehicles or 150 kW on some of our base brands. That combination of high-voltage charge and high temperature can cause some conditions in achieving fast charge rates.”