Greg Gardner

Detroit Free Press

General Motors will begin testing a fleet of autonomous Chevrolet Bolts on public roads around metro Detroit, CEO Mary Barra said this afternoon.

GM becomes the second traditional automaker to test a fully autonomous vehicle on public roads outside their own campuses and proving grounds. Ford has done some testing on public roads since July 2015.

"Being here where we can get the cold, snow and all the different weather conditions, with the support of our Warren Technical Center and Milford Proving Grounds, is very important," Barra said.

Barra said the autonomous Bolts will be assembled beginning early next year at the Orion Assembly plant in Oakland County.

"We expect to be the first high-volume auto manufacturer to build fully autonomous vehicles in a mass-production assembly plant," she noted in a blog Thursday on LinkedIn.com.

GM earlier this year acquired Cruise Automation, a San Francisco start-up that has developed much of the sensors, cameras, LiDAR and radar that enables the cars to drive with little or no human direction.

This isn't the first testing of these cars on public roads. GM and Cruise Automation have tested a small fleet in San Francisco and Scottsdale, Ariz. It currently has 40 Bolts equipped with the autonomous hardware and is planning to build an unspecified additional number at the Orion plant.

One of the challenges will be how the cars perform in harsh winter weather. In the first versions of autonomous driving systems, the algorithms, sensors and cameras have struggled when the lane markings on roads are obscured by snow or even heavy rain.

Uber has been testing a fleet of self-driving Ford Fusions and Volvo XC90s in Pittsburgh. It started testing in San Francisco earlier this week, but the California Department of Motor Vehicles stepped in to stop Uber because the company had not obtained the proper licenses.

GM's announcement comes less than a week after Gov. Rick Snyder signed a package of four bills aimed at positioning Michigan as a hub for development and testing of self-driving cars.

The new law allows:

Testing of vehicles without steering wheels, pedals or needed human control.

Automotive and technology companies to operate self-driving vehicle ride-sharing services.

Self-driving vehicles to be sold for public use once the technology has been tested and certified.

"We applaud GM's leadership in the mobility space, and their continued commitment to Michigan," said Steve Arwood, CEO of the Michigan Economic Development Corp., in a statement. "This announcement of additional research, testing and manufacturing all happening in Michigan also further cements our Planet M campaign and the fact that the future of mobility is happening and advancing right here."

In July 2015, Mcity, a 32-acre test site designed for autonomous and connected vehicles, opened on the University of Michigan North Campus. Last month, work began on a larger facility to be known as the American Center for Mobility on the site of the former World War II bomber plant in Willow Run.

Neither Barra nor other GM executives who attended an event Thursday would comment on when the self-driving cars will be available to the public, most likely through the ride-hailing service Lyft in which GM holds a 9% stake.

Many technical and safety questions remain unanswered about autonomous vehicle technology. The National Highway Traffic Safety Administration proposed a broad set guidelines. The agency is reviewing comments and criticisms of those guidelines from a variety of automakers, suppliers, safety advocates and consumer protection groups.

Contact Greg Gardner: 313-222-8762 or ggardner@freepress.com. Follow him on Twitter @GregGardner12.