View Photos of the 2019 Audi A8L

Overall length increases slightly to 208.7 inches, though, and the Audi's rear quarters remain supremely accommodating—complete with an optional foot massager that folds out of the back of the front passenger's seat.

The A8L's standard 48-volt hardware consists of a 0.5-kWh lithium-ion battery and a belt-driven alternator-starter, which powers an engine stop-start system that can seamlessly cut and refire the engine while coasting at speeds as high as 14 mph.

Notably, the electric motor never assists the engine in sending torque to the wheels. Although the A8L bettered its 27-mpg EPA highway rating by 3 mpg on our 75-mph fuel-economy loop, it only matched its so-so 19-mpg city estimate during its time with us.

In other markets, Audi offers the A8 with its Traffic Jam Pilot system for Level 3 hands-free driving in certain situations.

Although U.S. models can be outfitted with all the necessary hardware, including a forward-facing laser scanner, Audi is not enabling the system in the U.S. The company cites an absence of federal legislation, fragmented state laws, and disjointed infrastructure stand­ards as reasons why we can't go hands-free just yet.

We're not missing out on all that much, though, considering that the system works only up to 37 mph on limited-access highways that have a physical barrier between opposing traffic.

For now, opting for the $4150 Executive and $2750 Driver Assistance packages adds a host of conventional, if advanced, driver aids—adaptive cruise, lane-keeping and blind-spot assistants, and an impressive virtual 360-degree camera system with active collision warnings—as well as numerous other luxuries.

adillac's Super Cruise and BMW's new Extended Traffic Jam Assistant are the only truly hands-free driving features on sale today. And similar systems from Mercedes and Tesla are more adept at lane-centering than the Audi's, which has the A8 ping-ponging between the lines more than we'd like.

Equipped with its optional four-wheel-steering setup and a $1200 set of 20-inch wheels wrapped in 265/40R-20 Goodyear Eagle F1 Asymmetric 3 summer tires (19s with all-seasons are standard), our test car circled the skidpad at an impressive 0.93 g, topping comparable entries from BMW, Lexus, and Mercedes.

Likewise, its 14.8-inch front and 13.8-inch rear brakes, controlled by a firm, easy-to-modulate pedal, hauled the 4995-pound A8L down from 70 mph in a scant 149 feet, a full 10 feet shorter than any of its peers could manage, regardless of tire selection.

That sense of serenity is bolstered by the relaxed demeanor of the A8L's sole powerplant (for now), a turbocharged 3.0-liter V-6 good for 335 horsepower and backed by a 48-volt electrical system. A V-8 will join the lineup later, as will a V-6 plug-in hybrid.

The A8's marquee features also include an active suspension system that will be available later this year and will be able to lift the body to better protect occupants from side impacts.

In daily use, it will scan the road ahead to predictively raise or lower the body at each corner, gliding the A8L over bumps and potholes.

We've yet to experience how the setup performs on our familiar thoroughfares, but the standard air springs and adaptive dampers manage the multilink front and rear suspensions with the isolated plushness and balanced dynamics befitting a swanky sedan starting at $84,795.

While the A8L's sheer size is never far from mind, Audi engineers imbued the car with both fine body control in corners and an imperturbable solidity at triple-digit speeds.

The steering is laser precise, if rather muted in feel. Its weight changes through the array of Drive Select modes (Comfort, Auto, Dynamic, and Individual), which also tweak the attitude of the engine, transmission, and dampers.

We'd feel pressed to beg for greater feedback if the Audi weren't such a serene cruiser, emitting only a 69-decibel purr at wide-open throttle, quieter than all its rivals.

While the new 3.0T engine lacks the more characterful sound and power delivery of the supercharged V-6 it replaces, it smoothly unfurls 369 pound-feet of torque from just 1370 rpm and mates well with the refined calibration of Audi's ZF-sourced eight-speed automatic.