General Motors announced today that it will expand its advanced driver-assistance system’s range by 100 percent with the addition of new roads to the Super Cruise network in the United States and Canada.

The automaker says it will add hundreds of thousands of miles of road on which Super Cruise can be used. That will bring the total distance where the system, which only works on highways that have been mapped by GM, is effective to 400,000 miles (643,740 km) in North America, per Reuters.

Super Cruise was, at first, only available on Interstate Highways, but this expansion will make it useful on many additional state and federal routes. In addition to divided highways, the update will include undivided roads with notable additions to the system including the Mother Road, U.S. Route 66, the Pacific Coast Highway, CA Route 1, the Overseas Highway, U.S. Route 1, and the Trans-Canada Highway.

Read Also: GM And Ford Want To Put 5,000 Autonomous Vehicles On The Road Without Pedals Or Steering Wheels

Super Cruise uses LiDAR map data, real-time cameras, radars, and GPS to keep vehicles in their lane and moving happily along with traffic. It can now perform driver and system-initiated lane changes to pass slower traffic and to move out of a lane that’s ending.

Being a limited system, though, it monitors the driver’s head position and eyes to ensure that they are always paying attention and in control of the vehicle, unlike systems from automakers like Tesla, which have been abused by drivers.

“GM is all in when it comes to accessible advanced driver assistance technology. We are adding Super Cruise to more vehicles than ever, and on more roads for more customers to experience,” said Mario Maiorana, GM chief engineer, Super Cruise. “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.”

GM says that the Super Cruise will be delivered at no extra charge to new vehicles in the GM portfolio built on the VIP electrical architecture. Available as an over-the-air update, the addition will be offered later this year on Super Cruise-equipped models.