Think back to your youth - no matter your age - and picture a proper luxury car from that era. Unless you're a precocious teen stumbling upon this site, I'm certain you imagined some sort of plush sedan. Whether a powerful yet reserved Mercedes-Benz, a Broughamtastic Cadillac Sedan DeVille, or a stately Lincoln Town Car, the traditional three-box sedan has defined the ultimate in automotive opulence since the Second World War.

No longer, it seems. Today's titans of industry are wholly given over to unfamiliar affections, finding happiness in another kind of conveyance: the big SUV. Whether Escalade, Navigator, or G-Class, rising above the poors means being seen above the poors. If design govern in a thing so large, whither tradition?

Since the default for extravagant luxury seems to be a full-size SUV, the traditional big floaty sedan's days seem to be numbered. Does the 2018 Cadillac CT6 rage, rage against the dying of the breed? Or does it go gentle - with Super Cruise - into the good night?

Super Cruise is indeed the killer app here. Cadillac is careful to not use the term "autonomous" when describing the system - it's called a "hands-free driver assistance feature" here - but it will maintain speed and lane on the interstate, even in curves.

For those of you unfortunate enough to have experienced my beloved hometown of Columbus, Ohio, perhaps the "Hospital Curve" on State Route 315 will be familiar. The six-lane divided highway was built in the 1960s to ease traffic flow from the northern suburbs into downtown Columbus, but the road makes a sharp S-turn near two hospitals to (mostly) avoid a century-old cemetery. It's the site of a good deal of congestion, as well as frequent accidents caused by inattentive motorists.

So, it was with this highway in mind that I began my Super Cruise testing - yes, mom, with my hands inches from the wheel, and fully alert with sugar-free Monster.

Super Cruise can only be engaged on limited-access divided freeways - think interstates, with a defined median or Jersey barrier dividing traffic. It seems that Super Cruise isn't happy at night. I drove the CT6 south from Detroit in the wee hours, and the system kept flashing red lights from the steering wheel and buzzing my seat telling me to take over after a few seconds of hands-free driving. The next day, however, Super Cruise let me cruise in daylight comfort.

The all-seeing eye is a funky camera that sticks up from the top of the steering column. It watches the driver for signs of alertness, and will issue a warning before handing control back over.

Long story short, Super Cruise handled the Hospital Curve perfectly. The cruising speed dropped slightly simply from the scrub of the tires, from roughly 68 mph to about 65 mph, and resumed once the curves faded in the rear-view.

Good news for those who don't need the size of the CT6 - Super Cruise will be available across the entire Cadillac lineup by 2020.

I rather loved the night-vision camera fitted to the CT6. While Super Cruise didn't help me much as I drove home late that night, the infrared display in the 12-inch gauge cluster showed a heat signature of a sneaky Ohio State Highway Patrol vehicle lurking behind tall grass in a median. I spotted the cruiser, dropping my speed to something a bit less conspicuous.

That said, the CT6 doesn't exactly elicit a ton of attention from passers-by. It's yet another in a long line of familiar, Art-and-Science-y folded paper designs from Cadillac. It's handsome, certainly, and looks right in line with the rest of the Cadillac lineup, but it doesn't really stand out. I do rather like the LED bars vertically flanking the headlamps, defining the fascia of the CT6. In a way, the bright vertical daytime running lights remind me a bit of iconic tailfins of the '50s, but obviously on the wrong end of the car.

The interior is where the CT6 shines. The seats are incredibly comfortable for long days behind the wheel. The massage feature was especially welcome after a too-long window-seat flight from the west coast, easing my back into something resembling normalcy. That the heated, cooling, massaging, adjustable chairs are available at all four places reminds me that a big luxury sedan isn't just for the driver - it's for those being driven.

In this case, as usual, the chauffeured were preteens. And they were pleased. Legroom in the rear is cavernous - the eldest was able to change into softball cleats without removing her seatbelt or kicking the seat in front of her.

The wireless charging pad is ingeniously located aft of the shifter, integrated just below the lid for the center console. My Samsung Galaxy S7 fit perfectly in this spot - it's mostly hidden, but easily grabbed when time to leave the car. If your phone doesn't support wireless charging, the slot is still perfectly situated to allow a USB or Lightning cord to connect the phone to the included Apple CarPlay or Android Auto.

Also superb was the Bose Panaray sound system. Of course, with 34 speakers, it should be. I'm baffled, however, by the squat center-channel speaker that rises from the dash upon engine startup, lowering again on shutdown. It doesn't affect visibility one iota when raised, so why not leave it up permanently? I suppose, raised as I was on (British) cars that always had some electrical fault or another, I'm just expecting an eventual failure. I have to believe that speaker lift is just a bit of theater.

The powertrain is what one would expect from a sedate luxury sedan: powerful, but not overwhelming. It's not the massive 500cid V8 found in a 1976 Eldorado, certainly, but the stout, twin-turbocharged V6 powers all four wheels with plenty of thrust and little drama. A pedal mash allows a bit of engine note to filter through to the cabin, but otherwise the drive is silent and serene. It's a much more relaxed drive than in a big SUV, as the low center of gravity keeps the passengers from being tossed about without resorting to heavy springing. While the magnetic ride control handles most road imperfections brilliantly, an errant pothole did cause a bit of shudder through the cowl and into the ****pit.

Trunk space is quite good - Cadillac lists 15.3 cubic feet in the way back. Obviously, it's not what one would find in a luxury SUV, but covered, locked trunk storage is an asset for many buyers. Back when I still played golf, I hated leaving my clubs in the open cargo area of an SUV while at the office. I much preferred a secure trunk to hide those valuables.

That's what will keep some buyers in luxury sedans, I believe. The driving dynamics are better - even though the 2018 Cadillac CT6 is definitely no sports sedan - and secure trunk space is important. I prefer driving the CT6 over an Escalade, certainly, and this remains a bulwark against the crossover tide.

a version of this review first appeared on