In polite circles, the Impala would be called beefy. The Feds call it a full-size sedan. In truth, it's not a lot bigger than an Azera, a Passat, or an Avalon--but it packs a lot of room under its roofline, shaming the inefficient layout of the Ford Taurus, for one.
The Impala's overall length of 201.3 inches draws down to 111.7 inches between the wheels--compared to 106.3 inchess of wheelbase on, say, a three-row Kia Sorento crossover. It's 73 inches wide, too. Compared to the last Impala--now the fleet-only Limited--the 2014 version has about 3.5 inches more front-seat leg room and 2.2 inches more in the back seat.
Open the wide, tall doors, and the Impala V-6's nicely shaped seats aren't too deep a knee-bend away. At least five different seats are specified across the lineup, but that's mostly because of optional seat heating and ventilation--only the base versions are cloth. Leather-clad versions on the LTZ have a middle grade of hides covering them, better than the cloth/vinyl seats in look and just slightly, in feel, since lumbar adjustment comes with them standard. Head and leg room are more than enough for even 99th-percentile types; the Impala's one of the rare new cars where you can power the driver seat too low and too high.
The rear seats aren't quite as close to premium, but leg room is only an inch or two short of limousine status. The cushion lays almost flat, it's a bit short for the car's size--and even so, headroom isn't extraordinary. I made close contact with the headliner, and at six feet tall, I'm not the worst-case scenario for backseat use. Two adults will have enough space for a pre-teen between, though, and the seats can be fitted with bite-sized head rests shaped like old-school car bumpers. Score one for visibility.
Even with five passengers, filling the Impala's cargo bins will take some work. The trunk's 18.8 cubic feet, second only to the Taurus' 20-cubic-foot whopper. It's a little shallow, but the trunk floor is flat and extends deeply beneath the rear glass. The doors all have long bins with bottle holders; the center console can swallow a shoebox, a smartphone in either a rubberized tray or a bin hidden under a lid, and two drinks. If you're in an LT or an LTZ, there's a hidden chamber behind the MyLink LCD touchscreen, too--tap a button and the screen rises so you can stow goodies, then lock it out in a valet mode with a code you can enter and change.
Chevy has tuned the Impala's interior for quieter rolling ambience. Four-cylinder models will sport active noise cancellation, like Chevy's Equinox, and the plusher versions get thicker glass and more sound deadening. The impression of noise control is a good one.
It's in the area of fit and finish where the Impala can get a better sense of direction when it comes in for the inevitable mid-cycle refresh. The busy twin-cowl cockpit is covered, studded, paneled, and draped in so many different materials and textures, it's almost a parlor game to find and name them all. The seat-heater surround is a glitzy, flecked black plastic; the door caps are soft to the touch but openly grained. Consistent, not insistent--that's is all that's keeping the Impala from fully connecting with the elusive quality genome.