General Motors has announced a significant expansion to the road network on which its Super Cruise hands-free driving tech will be available.

Later this year, the advanced driver assistance system (ADAS) will be able to operate on 400,000 miles of roads across the U.S. and Canada, including non-divided highways. This will constitute a doubling of the coverage currently offered in North America.

Super Cruise launched a few years ago on the Cadillac CT6 and has been subsequently added to other GM models. It uses precision lidar mapping data, real-time cameras, radars and GPS to allow braking, acceleration and, in some instances, lane changes, delivering a hands-free driving experience on compatible roads.

However, a human must be behind the wheel at all times, and they are constantly monitored to ensure they are paying attention. Super Cruise is rated a Level 2 driver assistance system, as defined by the Society of Automotive Engineers.

Unlike Tesla’s Autopilot – which can be activated on most roads if the system detects visible lane markers – use of Super Cruise until now has been limited to divided highways that GM had mapped and approved for use.

That is now changing. 

“This expansion will enable Super Cruise to work on many additional state and federal routes, a combination of undivided and divided highway roads,” according to GM.

A total of around 200,000 miles have been added, including large sections of some of the most notable roads across North America. Among the stand-outs are parts of U.S. Route 66, the Pacific Coast Highway (CA Route 1), the Overseas Highway (U.S. Route 1) and the Trans-Canada Highway.

The news comes as GM prepares to significantly expand the number of vehicles available with Super Cruise. Company president Mark Reuss has previously suggested that no fewer than 22 GM models will have the functionality by 2023, including the eagerly awaited Tesla-rivaling Cadillac LYRIQ EV.

“GM is all in when it comes to accessible advanced driver assistance technology,” said Mario Maiorana, GM’s chief engineer, Super Cruise. “We are adding Super Cruise to more vehicles than ever, and on more roads, for more customers to experience. We are pursuing what we believe to be the most comprehensive path to autonomy in the industry with responsible deployment of automated driving technology like Super Cruise at the core of what we do.”

The network expansion will be available later this year with GM vehicles built on the firm’s VIP electrical architecture the first to benefit. These include the Cadillac Escalade, CT4 and CT5, Chevrolet Silverado and GMC Hummer EV and Sierra. It will be delivered over the air at no additional charge.