The GM logo is seen at the General Motors Lansing Grand River Assembly Plant in Lansing, Michigan October 26, 2015.
The GM logo is seen at the General Motors Lansing Grand River Assembly Plant in Lansing, Michigan October 26, 2015. Reuters / Rebecca Cook

General Motors Co said on Wednesday owners of certain vehicles equipped with its Super Cruise assisted driving system will now be able to use it on 400,000 miles (643,740 km) of North American roads, doubling the current operating area as Tesla and other automakers race to deploy hands-free cruising technology.

GM's Super Cruise system, like Tesla Inc's Autopilot system, is a driver assistance system, and does not enable true autonomous driving. Spurred by Tesla's aggressive deployment of Autopilot, and Tesla Chief Executive Elon Musk's promises of a more advanced "Full Self Driving" system, GM, Ford Motor Co, Volkswagen AG and Mercedes-Benz AG are racing to deploy competing partial automation technology in major markets.

At the same time, safety regulators are showing concern that drivers do not understand that Autopilot and similar systems are not designed to take over driving in every circumstance.

The GM system's sensors and software allow a motorist to cruise with hands off the wheel on highways that have been mapped in detail. But the driver is expected to stay alert and ready to take over the car. GM uses technology to monitor the driver, and Super Cruise will sound alarms or slow the car to a stop if it detects that a driver is not responding.

Starting later this year, GM plans to enable vehicles equipped with Super Cruise and the company's latest vehicle electronic system to operate hands-free on major, undivided highways in the United States and Canada, as well as additional miles of divided, interstate highways. Currently, Super Cruise operates only on interstate, divided highways.

The expansion, enabled by wider digital mapping, will allow owners of properly equipped GM vehicles to cruise hands-free on stretches of Route 66 in the U.S. West or the Trans-Canada highway in Western Canada, GM said.

Many of the new roads GM has mapped are in rural, heartland states where GM pickup trucks are popular. GM plans to offer Super Cruise as an option on its Chevrolet Silverado and GMC Sierra large pickups later this year. GM has said previously it intends to offer Super Cruise as an option on 22 models by the end of 2023.

Depending on the model, Super Cruise costs $2,200 to $2,500 to add as an option.