It's easy to see how declining sales of the TrailBlazer and Envoy would make GM nervous. Meanwhile, crossovers have become red hot and GMC doesn't have one. What do you do?

In GMC's case, introduce the Acadia, a unibody with aspirations of being the most SUV-like crossover on the market. With three rows of seats standard, a functional cargo area, towing capacity of up to 4500 pounds, and plenty of amenities, it's a valid argument. Length and width skew closer to the Yukon, but it sits lower than the Envoy.

The short front overhang houses GM's all-aluminum 3.6-liter V-6, which is transversely mounted in an engine bay the manufacturer acknowledges is big enough to contain something larger. The V-6 (17-18 mpg city/24-26 highway) has variable valve timing and makes 275 horses and 251 pound-feet of torque. Filled with people, climbing a grade may test the upper limits of the V-6, but when the Acadia's empty, it does provide enough punch around town. On twisting roads, the chassis proved solid and mostly quiet. City driving will highlight the Acadia's size, but the GMC drives like a smaller vehicle, one that's easy to maneuver through rush-hour traffic. Be careful, though: Between the high beltline, small side mirrors, and sizeable C-pillars, visibility is compromised. The standard ultrasonic parking assist definitely comes in handy. Expect a backup camera to become available later this year.

Behind the V-6 is the Hydra-Matic 6T75, a new six-speed designed for performance off the line and fuel economy at freeway speed. First/second/third shifts are quick, nearly jumpy. Once out of that and into the upper gears, fourth through sixth engage slower and more smoothly, but the drivetrain takes some convincing to eke out power.

At the track, the Acadia is at a disadvantage. At 8.4 seconds to 60 mph, it's faster than the Pacifica and Tribeca (9.6 and 9.2), though slower than the Murano (8.1) and the V-8 Durango and Explorer (8.0).

Braking from 60 requires 134 feet, and its stops at the track and on the road are smooth and predictable. Front drive and traction control are standard, but our tester came equipped with all-wheel drive. This system keeps nearly all the power at the front wheels under normal conditions, but can redirect up to 99 percent of the torque to the rears when needed. Four-wheel discs with ABS and StabiliTrak are standard. So are the Acadia's six airbags--two dual-stage up front, two side-impact airbags mounted in the first-row seats, and two head curtain side-impact airbags that cover all three rows.

All Acadias come with three rows, and all receive the Smart Slide function in the second row. Tug on one handle, and the bottom cushion is pulled up, sitting flush against the back of the front seat--the rest of the second-row seat slides forward on its rails, collapsing just behind the bottom cushion. With that single movement, the third row becomes one of the easiest to get into. And because the second row slides up to four inches, the extra legroom makes it easy to fit tall riders, which is good, because the backs of the front seats are covered by hard plastic panels.