For some time now, Cadillac has been touting itself as a maker of luxury cars for people who like to drive, but its top-end CT6 sedan will soon be available with a semi-autonomous drive system that will be able to take full control of the car in freeway driving.

General Motors’ announcement marks another step toward what seems like the unavoidable future of personal transportation, the driverless one that hardly requires a person to be in the vehicle.

But that day hasn’t arrived yet: Super Cruise will only work on limited-access roads, like multi-lane highways with what the automaker calls “defined on- and off-ramps.”

It will do so using an array of on-board cameras and sensors like those we’ve already become accustomed to in modern cars, but adds extra layers, in the form of super-accurate GPS data (four to eight times more accurate than traditional GPS, says GM) and a map database created using LiDAR (light detection and ranging) technology.

GM says its engineers have used LiDAR to map “every kilometre of limited-access highway in Canada and the U.S.” in order to provide the car with as much information as possible about the road ahead of the car.

Even with all of that technological firepower at the car’s disposal, Super Cruise won’t work on city or rural roads with intersections, because those situations present less-predictable variables and hazards than highway cruising.

According to the automaker, that’s not because the technology isn’t ready for prime-time, but rather that a measured rollout is a necessary step in building confidence in self-driving tech among consumers and industry regulators.

Also, Super Cruise won’t allow the human behind the wheel to pick up a newspaper or take a snooze. A camera on top of the steering column and infrared lights will monitor the driver’s head position and where he or she is looking.

If they’re not eyes-up, the car will prompt them to pay attention with a series of escalating warnings, and after a certain period of inattentiveness, the car will assume the driver is incapacitated and will safely pull the car over and alert first responders through OnStar.

Cadillac says Super Cruise will be available as an option in the 2018 CT6 Prestige trim across North America starting this fall.