GM announced that later this year their Super Cruise system will be able to work on 400,000 miles of roads in the United States and Canada.

Super Cruise, the “hands-free” advanced driver-assist system (ADAS) from General Motors, will soon be available on a lot more roads in North America. GM announced today that, later this year, the ADAS system will be able to operate on 400,000 miles of roads, including non-divided highways — which would essentially double Super Cruise’s current coverage in the US and Canada.

It represents a major expansion of Super Cruise’s capabilities at a time when US regulators are scrutinizing driver-assist features more closely and safety advocates are calling for more transparency, citing research that shows how new technology can create safety risks inadvertently.

Launched in 2017 with the Cadillac CT6, Super Cruise uses information from cameras and radar sensors embedded on the car, GPS data, and lidar mapping data collected by the company to allow for hands-free driving and, in some cases, automatic lane changes. It pairs this capability with a driver-monitoring system that uses an infrared camera to make sure the driver is paying attention to the road in case Super Cruise needs to hand back control to the driver.

Unlike Tesla’s Autopilot, which can be activated on almost any highway or road as long as the system spots visible lane markers, drivers are currently only able to use Super Cruise on divided highways that GM has laser mapped and approved for use. Up until now, that included just 200,000 miles of limited-access highways with concrete barriers dividing opposite lanes of traffic.

But, starting later this year, drivers of vehicles like the Chevy Silverado, GMC Hummer EV, or Cadillac Lyriq will be able to use Super Cruise on non-divided state and federal highways, which are sometimes called routes — main roads that connect smaller cities and towns. That includes the famed US Route 66, running from Chicago to Los Angeles; the Pacific Coast Highway, which runs along California’s coastline; the Overseas Highway, which connects Miami to the Florida Keys; and the Trans-Canada Highway, which transverses the country from east to west.