How Cadillac's Super Cruise System Works

CARS.COM — Fully self-driving cars may still be a long way off, but Cadillac is taking a big step with Super Cruise, a system that can steer, accelerate and brake in certain highway conditions. We first heard of it in September 2014, but Cadillac announced in early April that the semi-autonomous system at long last would come this fall as a $2,500 option on the 2018 CT6 full-size luxury sedan.

Related: Which Cars Have Self-Driving Features for 2017?

Today, GM’s luxury division released more details on the inner workings of Super Cruise. Here’s how it works.

What Makes Super Cruise Different?

Provided you’re paying attention and able to take over, Super Cruise can drive the car indefinitely in certain highway conditions. Cadillac calls it the industry’s “first true hands-free driving technology for the highway.” That’s the first time we’ve heard any automaker advocate full hands-free driving under certain conditions for a production car — and it comes straight from the top. In a statement, Cadillac chief Johan de Nysschen called it a way to offer “safe, simple hands-free driving for the highway.”

Audi may have similar language for the next A8 sedan in the summer, but for right now, hands-free is a big differentiator. Existing semi-autonomous systems still require a lot of driver involvement; even Tesla still calls its Autopilot feature a “hands-on experience.” We’ve previously observed Autopilot drive indefinitely with the right conditions, but Tesla updated the system in September 2016 to deactivate itself if you ignore warnings to hold the steering wheel. That’s still the case for the current iteration of Autopilot, Tesla confirmed today.

How Does Super Cruise Work?

Each car with Super Cruise has a network of cameras and radar sensors plus high-accuracy GPS that can pinpoint your position within 3 feet, said Kevin Kelly, an advanced technology spokesman at GM. Each car also has a database with every mile of limited-access divided highway in the U.S. and Canada, mapped through light detection and ranging technology. GM says it analyzed every mile of such roads to identify areas with sufficient conditions for Super Cruise to work — so if you approach an area where the highway ends, Super Cruise will prompt you to take over before that occurrs, according to Kelly.

It manifests itself through adaptive cruise control that works from stop-and-go conditions to highway speeds, plus automatic lane centering steering with no time-out so long as conditions are met, Kelly said. But rather than relying on lane markings or the position of the car ahead — both not-always-reliable guidelines used by conventional lane centering steering — Super Cruise primarily uses what Kelly calls the “blue line,” a virtual line down the middle of the road concocted by the lidar database. The database also alerts Super Cruise to forthcoming curves or elevation changes so it can change speed accordingly, Kelly said.

Will GM Update the Database?

Yes. GM is “remapping roads continuously, so we send new data down to the mapping system [on each car] via over-the-air updates,” Kelly said. “We are sending trucks back out to remap using the lidar, so they’re out scanning the roads continuously.”

What Happens If There’s Construction or Some Other Change That Hasn’t Been Mapped?

The centerline is the “primary” guideline for Super Cruise steering, Kelly said, but it’s not the only one. Super Cruise also accounts for your surroundings with other cameras and sensors, including downward-pointing cameras that analyze lane markings. The sensors are always trying to match up what they see with what’s in the database, and if there’s incompatibility — a new construction zone that GM hasn’t remapped yet, for example — Super Cruise notes that it doesn’t match the database and prompts you to take over, he said.

Do Cars With Super Cruise Have Lidar Scanners?

No. Super Cruise relies on GM’s lidar-mapped database that’s aboard the car, but it doesn’t add physical lidar sensors to the car, Kelly said.

How Does Super Cruise React to Merging Traffic?

Largely the same way any adaptive cruise control does. Super Cruise “acts similarly to ACC,” Kelly said. If somebody cuts you off, it “would flash the red light” to warn you of an impending collision or engage automatic braking, he said. Still, we’ve observed merging traffic as a common foil for many self-driving technologies, which often ignore the threat until too late and force you to hit the brakes first.

Driving is believing, so stay tuned for Cars.com’s firsthand impressions.

Can I Do Something Else While Super Cruise Drives?

No. Super Cruise includes a new Driver Attention System to ensure you won’t do that. DAS employs a camera atop the steering column that watches you to ensure attention with infrared lights to track head position. It has ultraviolet sensors, too, so it can work at night.

“It’s looking at where your head is positioned with the roadway, so it knows if you’re glanced down,” Kelly said. “We’re not following strictly eyeballs. We’re following position of the head.”

Turn away for too long and the system will alert you to pay attention. If you don’t, progressive warnings chime in, from a rumbling seat and visual alerts from the instrument panel to audible warnings and an illuminating light bar on the steering wheel. Continue to do nothing, and the system can bring the car to a stop and call for help via OnStar.

It can also detect no head movement.

“Let’s say something held up a [faux] head on a stick,” Kelly said. “If somebody held it up, and we could detect that the head wasn’t moving at all, that’s not normal.”

If it detects no head movement, the system could tell you to look down at the radio to prove you’re paying attention, he said.

Is This a Level 3 System?

No. Cadillac’s system takes a big step beyond today’s mass-market self-driving technology, but it still calls the system Level 2 — a reference to SAE International’s six-level classification of self-driving technology: Level Zero to Level 5. Indeed, the fact that Super Cruise requires you to monitor your surroundings signals as much. Level 3, by contrast, is where the car monitors the surroundings. Audi claims it will offer the industry’s first Level 3 system in the redesigned A8 early next year.