It’s not all happening in Silicon Valley.

General Motors has created a new team dedicated to autonomous cars at its Warren Tech Center, based in Detroit. There are already several hundred employees working on the development of its self-driving system, alongside test drivers already active in San Francisco.

“We’ve got several hundred people in this space right now … expanding to several hundred people more (by end of this year into next year),” said Ken Kelzer, vice president of global vehicle components to Detroit News.

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Inside the tech center, General Motors has developed an indoor track for car testing. Employees are also able to hail the autonomous Chevrolet Volt cars from outside of the building, using an app, which lets them test the self-driving system on public roads with traffic.

Adding another billion to GM’s autonomous spending

The tech center redevelopment is said to cost GM $1 billion—the same price it paid for self-driving startup Cruise Automation.

“The nice thing about the Tech Center is there are a lot of different traffic maneuvers,” said chief technology officer, Jon Lauckner. “For example, we have roundabouts where you have to merge on and merge off. It turns out to be a fairly complicated situation. There are definitely medians, left turns across traffic, you know the kinds of things you’re going to find definitely in an urban environment. And the kinds of things that are going to allow us to basically refine and further develop the sensing and processing that we’re going to need to have a fully autonomous vehicle in the future.”

GM expects the combination of in-house and real-life testing to propel them ahead of other automakers currently working on self-driving systems, though it is behind Tesla, Google, and Daimler, who have made large investments or managed millions of miles already.

The hailing services inside the building are expected, considering GM spent $500 million to own a part of ridesharing app Lyft earlier this year. GM wants its Chevrolet Volt to be a large part of Lyft’s driverless fleet, and in the meantime plans to sell a lot of the cars to drivers through prefered financing options.