GM is nearly doubling the road miles where drivers can use its partially automated driving system

General Motors is adding about 350,000 miles, or about 563,000 kilometers, of roadways in the U

DETROIT -- General Motors is adding about 350,000 miles (563,000 kilometers) of roadways in the U.S and Canada to the area where drivers can use the company's “Super Cruise” partially automated driving system.

The expansion nearly doubles the road miles where the system can run. It includes both limited-access divided highways as well as some two-lane roads connecting cities to smaller towns and smaller towns to each other, the company said.

GM said the driver-assist system is ready to handle some roads with intersections and crossing traffic, which have been troublesome for systems from other companies such as Tesla.

With the system, drivers can take their hands off the steering wheel, although they must be ready to intervene at all times because the vehicles can't drive themselves, GM said.

Tesla's Autopilot system has had trouble spotting and stopping for crossing tractor-trailers, with at least three deaths reported. The most recent was last July in Fauquier County, Virginia.