Roush, an engineering and specialty manufacturing company known for its custom Ford Mustang models, will assemble a test fleet of 100 Google prototypes in 2015, which Crain'sreported back in May. 

Google made an announcement last week that global suppliers with offices in Southeast Michigan, including Auburn Hills-based Continental Automotive Systems and Farmington Hills-based Robert Bosch LLC, would supply parts to the vehicles.

Chris Urmson, director of Google's self-driving cars program

The Silicon Valley-based Internet giant did not contract with an automaker for the project, Chris Urmson, director of Google's self-driving cars program, told reporters at last week's Automotive News World Congress in Detroit. Urmson did say that when the pod-like two-seater electric cars are ready for production, an automaker would be involved. He didn't specify whether the automaker would be one of the Detroit 3. 

Roush has leased additional space at 28220 Plymouth Road in Livonia and refurbished the space for the project, Maureen Crowley, director of corporate communications, told Crain's.

"We've built out a whole area specifically for this program," Crowley said. "It's been a great opportunity for us to expand upon our assembly capabilities." 

Crowley said Roush has made new hires in supply chain support and assembly, but declined to reveal specific numbers. Google is maintaining a tight lid on the project with non-disclosure agreements.