still not level 3

The Cadillac CT6 review: Super Cruise is a game-changer

No other car on sale can drive itself like this Caddy.

Jonathan M. Gitlin – Feb 22, 2018 9:00 am | 198

Credit: Jonathan Gitlin

Cadillac’s flagship CT6 might not have the best interior in its class. It might not have the sharpest, track-honed handling. It doesn’t have a butter-smooth V12 engine. It definitely doesn’t have the best infotainment system. And yet, it is carrying the most exciting technology being offered in any production vehicle on sale in 2018.

Called Super Cruise, Cadillac’s new tech represents the best semi-autonomous system on the market. In fact, Super Cruise is so good, I think General Motors needs to do everything it can to add it to the company’s entire model range, post-haste.

You sure sound excited about this thing

Regular readers will know this isn’t the first time I’ve written about Super Cruise. In fact, at last year’s New York auto show, we awarded it an Ars Best distinction in the “Automotive Technology” field—a bold move for new technology that we had yet to actually test.

But with almost 900 miles of Super Cruising under my belt now, I am glad to report that boldness paid off. This system really is that good. As long as its operational conditions are satisfied, Super Cruise will enable the CT6 to accelerate, brake, and steer without any need for you to touch the pedals or steering wheel. This can happen for hours at a time.

At its essence, Super Cruise is another one of those systems that combines adaptive cruise control and lane keeping. Forward-looking sensors measure the speed and range of any cars ahead of you to maintain a constant distance and also read the lane markers on either side to keep you centered within it. So far, so much the same as any number of systems from any number of OEMs. But Super Cruise adds a couple of other features that are missing in every other implementation—even in Tesla’s much-loved, somewhat-infamous Autopilot. What’s more, Super Cruise’s unique features will be critical for true self-driving cars in the future.

First up is the driver monitoring system (Cadillac calls it a Driver Attention System). This isn’t entirely unheard of; various car makers have been putting crude monitoring into vehicles to warn drivers when they might be getting too drowsy. The CT6’s DMS lives just on top of the steering wheel column, pointed at your face. Don’t worry! It’s not doing anything creepy like detecting your emotional state. (Do worry! Those kinds of systems are only a few years from showing up in our cars.)

Rather, the CT6 uses gaze tracking to know what you’re looking at. Here we encounter the first of the required conditions for Super Cruise to operate: you must be paying attention to the road ahead. Stop doing that for too long and a series of ever-more attention-grabbing alerts will follow. Keep ignoring those, and the system will disengage. Eventually, it will slow to a stop if there continues to be no driver input.

Ambient light isn’t an issue, because the steering wheel rim contains a number of infrared LEDs to illuminate you even in the dead of night, and DMS had no problems “seeing” my eyes even when I was wearing polarized sunglasses. If the DMS can’t see you because its line of sight is blocked by an object, it reacts the same way as it would if it could see you but you weren’t paying attention.

The second big difference between Super Cruise and everyone else is that it is geofenced. Regular old adaptive cruise control can be engaged anywhere. And lane keeping assists that autosteer for you only care that their optical sensors can read the lane markings. But Super Cruise is a bit pickier. It will only activate if you’re driving on a divided, limited access highway. More than that, it also has to be a highway that GM has lidar-scanned and added to its HD map, something the company has done for more than 160,000 miles (257,500km) of highways in the US and Canada thus far.

If both those conditions are satisfied—driver paying attention; car driving on a mapped, limited-access highway—you’re good to go.

Engage!

Before you can engage Super Cruise, you need to be already using cruise control (on non-mapped roads this works just the same as every other adaptive cruise system). Once you see a white Super Cruise icon on the instrument display, you can turn it on via a dedicated button on the multifunction steering wheel. At this point, the magic happens. The icon on the dash turns green, but more importantly so does a big, bright LED strip set into the top portion of your steering wheel. And now, you can go hands- and feet-free. As long as that light strip is green, Super Cruise is happy.

Take your eyes off the road for too long—about five seconds by my reckoning—and the warnings begin. The first of these starts the steering wheel light bar flashing. It remains green, but it wants your attention back on the road ahead.

Keep ignoring it and the alerts become more urgent. The light bar now flashes bright red, and there will either be audio warnings or the seat will start to vibrate angrily. (The choice of audio or haptic alerts is user-configurable.) Should you continue to ignore all of those warnings and keep your focus somewhere other than the straight ahead, Super Cruise disengages.

But I thought Autopilot was the best system in the world?

Up until this point, you probably thought Tesla’s Autopilot was the closest thing to a self-driving car any of us could buy. Certainly, when Lee Hutchinson did his 400-mile Model S road trip in 2016, that was probably true. But it’s not true today. For one thing, the Autopilot Lee used back then is different from the system currently being installed in Teslas. After falling out with supplier Mobileye, the electric car maker decided to go it alone, and the so-called Hardware 2 system, designed completely in-house, has yet to fully match the original system’s functionality.

For another, even though Autopilot will let you go hands-free for long stretches, its driver monitoring system is just a torque sensor on the steering wheel. YouTube is full of videos showing users defeating this feature with water bottles and citrus fruit, and this poor operational design was fingered by the National Transportation Safety Board as a factor in the fatal crash of Joshua Brown’s Model S in Florida in 2016.

For a more in-depth comparison of Super Cruise and Autopilot, I highly recommend this feature by Alex Roy over at The Drive.

The system will also use the red light bar and vibrations to alert you about an imminent disengagement, handing back control to the human. Unlike the “Level 3” driverless systems we’ve seen, Super Cruise doesn’t give you 30 seconds to take back control, but then again it has been designed not to have to solve that problem. As long as it’s active, Super Cruise knows you’re paying attention to the road, so there shouldn’t be any surprises.

When running, Super Cruise is an extremely good driver. It does not veer from one side of the lane to the other, and if the speed is set too high for an upcoming curve it will slow you down before you reach it. If you need to change lanes or adjust your trajectory in any other way via the steering wheel, the green LED will change to blue, and you have full control of the steering.

To return back to Super Cruising, simply let go of the wheel, and the LED turns green again. Like all cruise controls, dumb or otherwise, using the brake pedal will disengage it all. But if you need (or want) an extra burst of speed, using the accelerator will not interrupt it, it will merely make you go faster. Take note, this only works up to 90mph: exceeding such speeds will also cause the system to disengage.

Critics repeatedly point to “mode confusion” as a reason we shouldn’t pursue anything other than completely self-driving vehicles, pointing out that crashes happen when a driver thinks the car is in control, but the car expects the driver to be actively driving. And they’re not wrong. I experienced this while testing a Volvo XC60 recently on at least two occasions when I thought its Pilot Assist system was running when in fact it was not. I don’t think that would ever be a problem with Super Cruise, which is even less ambiguous about which mode you’re in than Nissan’s ProPilot Assist.

Again, this is a limited system that doesn’t work everywhere. During my testing (mainly on the highways between DC and Charlotte, North Carolina), I found it would disengage at highway junctions and also (but not always) when road construction meant the highway was narrowed and off its usual course. If I had one complaint, it would be that Super Cruise places the car slightly closer to the right-hand lane boundary than I’d prefer. But beyond that tiny quibble, I was deeply impressed with its ability to get me home from Charlotte safely after a long day of meetings and demos (with NASCAR, something you can read about in the next few weeks).

What else can the CT6 do?

If you’ve made it this far, congratulations! We’re 1,500 words into the review and I’ve yet to mention anything other than Super Cruise. But that’s OK, it really is a game-changer in my opinion. That’s not the only tech to be squeezed into the CT6’s handsome shell, however.

Another driver assist that I found extremely useful was the CT6’s night vision system. It’s less useful cruising at freeway speeds than low-speed driving, particularly since it’s tied into the car’s pedestrian detection ability. As pedestrians walk by, they are bounded by yellow boxes on the display, meaning it should be hard to run someone over accidentally even if they’re wearing an all-black outfit on a moonless night.

The CT6 also gets GM’s clever rear camera mirror. If you want, you can use it as a regular auto-dimming mirror. But flick the little lever that protrudes from the bottom, and it switches from reflecting light back at you to displaying a video feed from the rear-view camera. We first saw this on the Chevrolet Bolt EV, and you can check out a video of how it works from our LA Auto Show coverage, but the advantage is a much wider field of view than a traditional mirror. On the other hand, it does take a few minutes to adjust to since the focal distance is now fixed on the pixels and not infinite.

That camera is one of four that are used for 360-degree parking. Together with haptic feedback in the seat (it rumbles when you get too close to an obstacle), this makes maneuvering the CT6 at walking speeds extremely easy despite its size. But the cameras also have another party trick: for a while now, some GM vehicles have allowed you to save video from their cameras onto an SD card. It’s a feature that first showed up in the Chevy Corvette, but it’s also here in the CT6. Unlike in the sports car, it serves another purpose, activating in the event of someone tampering with the car.

The CT6’s tech isn’t all wonderful, unfortunately. Unlike every other GM vehicle that uses MyLink for infotainment, Cadillac has its own system, called Cue. It’s not terrible, and it does include Android Auto and Apple CarPlay. But in terms of UI it’s far behind the systems you’ll find in similar flagship sedans from Audi or BMW. I was particularly frustrated with the way Cue displays maps, but any infotainment-induced frustrations were so offset by Super Cruise’s awesomeness that I don’t think it matters.

Looks sharp, comfy inside, clever engineering

The CT6 is instantly recognizable as a Cadillac, adhering to the brand’s “Art and Science” design philosophy. It’s a handsome car, particularly from head-on thanks to the distinctive LED daylight running lights and the big bold grill. There’s no getting around the fact that it’s a large car, though—204 inches or 5.2m, in fact.

The advantage of being big on the outside is that there’s a lot of room on the inside, of course. Front- and rear-seat passengers get acres of legroom (OK, 42.3 inches/1m front, 40.4 inches/1m in the rear). And both front and rear seats will massage their occupants. This might seem frivolous, but on long drives it really is a welcome feature. Each rear seat also gets its own 10-inch video screen. From the driver’s seat, the ergonomics are good, and you can adjust almost everything in Cue via the buttons on the multifunction steering wheel.

The interior isn’t quite as elegant as rivals from BMW, Mercedes-Benz, or Audi—but none of those luxury sedans can drive themselves the way the CT6 can. Value for money is relative, and there’s no denying that, at $89,290, our test CT6 isn’t exactly cheap. But it is fully loaded—none of the features I’ve written about are optional extras. That makes it cheaper than a top-of-the-line S-Class, 7 Series, or A8, all of which will set you back at least six figures.

There are a few other interesting technical details hidden within the CT6. Its chassis makes use of aluminum (extruded and cast) as well as steel. That weight saving means it doesn’t break the 4,000lb barrier—at 3,926lbs (1,780kg), it’s several hundred pounds lighter than most of its competitors.

Power comes from a 3.0L twin-turbo V6, which generates 404hp (301kW) and 400ft-lbs (542Nm). Other engines are available, including a plug-in hybrid, but only the 3.0L twin-turbo and a 3.6L naturally aspirated V6 are available in the Platinum trim CT6es, which are the only models to get Super Cruise. The EPA rates the twin-turbo CT6 at 21mpg combined (18mpg city, 26mpg highway). It is helped a little in this regard through cylinder deactivation, and (shockingly!) I was able to get pretty close to those figures, averaging almost 25mpg over 900 miles.

Regardless of the engine, power is transmitted to all four wheels via an eight-speed gearbox. It’s the same eight-speed used in the Corvette, and you can pick your own gears if you choose via the paddle shifters. All CT6s also get rear-wheel steering. The rear wheels can turn up to 3.5-degrees in the opposite direction to the front wheels at low speeds to boost agility (in effect shortening the wheelbase) and in the same direction as the front wheels at freeway speeds to increase stability.

As with all of these big, powerful sedans, their handling prowess is rarely likely to be tested by most owners. Theoretically you could take it to the track, but physics is physics, and it’s still a fairly heavy and quite large machine. If pushed, I’d say the BMW M760i is sharper—it weighs about the same and has an extra 200hp—but that car is also more than $64,000 more expensive. Not to mention, it doesn’t have Super Cruise.

Bring Super Cruise to the people!

Sadly, the same could be said for everything else on the market right now. So here’s my unsolicited advice to GM: do whatever it takes to make Super Cruise an option in every MY2020 vehicle you sell. Hell, make it standard equipment in as many as you can afford. (Full disclosure: Alex Roy had this idea first.) Because it really is so much better than anything else out there, what better way to convince the American car-buying public that you’re actually really good at this technology stuff?

GM is the only other company anywhere close to Waymo when it comes to self-driving technology; yet, if I were to ask 100 people whether they thought GM was better than Tesla at this, I am willing to bet money the overwhelming majority would say no. So go on, GM, spread the love across your brands, your trucks, your SUVs. I bet your share price would start, ahem, cruising.

Listing image: Jonathan Gitlin

Jonathan M. Gitlin Automotive Editor

Jonathan is the Automotive Editor at Ars Technica. He has a BSc and PhD in Pharmacology. In 2014 he decided to indulge his lifelong passion for the car by leaving the National Human Genome Research Institute and launching Ars Technica's automotive coverage. He lives in Washington, DC.

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