Driven: 2010 Lexus RX 450h

February 9, 2010

In addition to the new Lexus HS 250, Lexus has an entire line of hybrids that are almost indiscernible from a distance from their gasoline-only counterparts. Of those, the bestseller is by far the RX 450h, which brings a hybrid halo to this very popular luxury crossover.

We've had a number of engineers tell us that the best pairing for a hybrid vehicle includes a small, efficient gasoline engine that's relatively torque-weak, combined with a relatively strong electric-drive system. That way, the electric motors supply the torque needed for responsiveness and grunt off the line at traffic lights, while the gasoline engine does its part for passing and expressway cruising.

That's not the case for the 2010 Lexus RX 450h, which has, as part of its system, a 275-horsepower, 3.5-liter Atkinson-cycle V-6 that's actually very torquey on its own. It's quite possible Lexus could have achieved better mileage this time around with a four-cylinder as part of the system.

The simple answer, we suspect, is that it's all in the name of refinement. While the new 2010 Lexus HS 250h gets loud and boomy when you accelerate moderately or rapidly, as we reported in a follow-up drive last week, the RX 450h feels all the part of a Lexus. Drive it gently and you'll glide from stops in electric-only mode, with the V-6 almost imperceptibly kicking on at 20 or 25 mph, typically. Drive it a little more rapidly, to go with the flow of traffic, and the V-6 thrums in the background, with the continuously variable transmission generally keeping the revs well below 2500 rpm unless you're close to full throttle.

2010 Lexus RX 450h

2010 Lexus RX 450h

Even then, a stomp to the floor doesn't betray that Lexus smoothness, though it's accompanied by a bit of a high-pitched whine. Altogether the system makes 295 hp, with lots of available torque, so the powertrain feels relaxed and up to the task in everyday driving—and again, almost indiscernible from a non-hybrid crossover.

Although we didn't get a chance to test the traction available from the RX 450h's all-wheel drive system, it's worth mentioning that it's a very unusual arrangement. With electric drive motors in front and in back, the system coordinates them for best traction, along with the best regenerative braking to keep the battery pack charged. The back wheels are exclusively electric-driven.

The previous-generation version of the RX hybrid—the RX 400h—felt a little uneasy at highway speeds, but the RX 450h feels very settled at a 70-mph cruise. Still, driving the RX 450h is a numb, detached experience, with the steering quick and responsive but not relaying any feel of the road. Ride quality is supple, and the cabin is quiet, but as we said with the RX 350, the front seats have an odd contouring that digs into shoulder blades, and headroom is surprisingly tight. Rearward visibility isn't so great either.

We've had plenty of time now to use the Remote Touch controller, which blends some of the attributes of a mouse and trackball, and it's not as intuitive as it first seems. Initially it feels computer-mouse familiar, but even after you're past the learning curve you still have to look very deliberately to the screen, unlike rival systems like iDrive where the learning curve is a little sharper but you learn haptic/directional shortcuts that—at least with the newer version of iDrive—don't take your eyes off the road as much.

The test RX 450h had a eyebrow-raising $15,000 worth of options, including heated and ventilated seats, rain-sensing wipers, DVD entertainment, XM NavTraffic and NavWeather, the heads-up display, LED headlamps with intelligent high beams, Mark Levinson surround sound, and a $4,700 Luxury Package that included Semi-Aniline leather trim, a moonroof, a power hatch, and many other interior upgrades.

Angular Rear Exterior View - 2010 Lexus RX 450h AWD 4-door Hybrid

Angular Rear Exterior View - 2010 Lexus RX 450h AWD 4-door Hybrid

Our observed fuel economy of 23 mpg—in about 110 miles of mixed driving—didn't even come close to the 30 mpg city, 28 highway EPA estimates. But a few months ago we drove a 2010 Lexus RX 350 and averaged just 17 mpg with a similar mix of driving. That's a very noteworthy 35-percent improvement, but one that would take a long time to pay off the $5,000 difference between the two models.

Let's face it; the RX is a feel-good vehicle for families who don't get the least bit excited about driving but want to cut their fossil-fuel use and still have their luxury.

And for that we still don't think the badging and the lower-case 'h' are big enough.

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