2010 Lexus RX 450h

Remember that Seinfeld episode where George Costanza said, "I would drape myself in velvet if it were socially acceptable?" Well, sitting in the 2010 Lexus RX 450h is like being draped in velvet, and, with the economical hybrid drivetrain, it is socially responsible.

Lexus vehicles show a level of luxury unequaled in today's market by all except cars costing hundreds of thousands of dollars. Run your fingertips along the soft headliner, open and close the whisper-quiet power windows, and you will see what we mean.

And it doesn't hurt that the 2010 Lexus RX 450h is one of the more technically advanced cars available today. This iteration of Lexus' hybrid, five-passenger SUV gets a new cabin tech package with a hard-drive-based navigation system, iPod integration, Bluetooth stereo streaming, and voice command that lets you dial contacts by name. The hybrid power train moves the RX 450h along under electric power only at slow speeds, mixing in drive from the 3.5-liter V-6 for acceleration or speeds above 30 mph.

Hybrid efficiency
The 2010 RX 450h and nonhybrid RX 350 share body and cabin tech, but the RX 450h's hybrid drivetrain makes a world of difference. When we had the 2010 RX 350 in a few weeks ago, we weren't terribly impressed by the engine and transmission. The hybrid power train in the RX 450h makes this vehicle more powerful while at the same time getting much better fuel economy. If anything proves the value of a hybrid, it's that comparison.

Although the engine size is the same between both SUVs, the RX 450h uses an Atkinson cycle for its intake and exhaust strokes, gaining efficiency at the expense of torque. But that's OK, as the hybrid system's 167-horsepower electric motor punches in the needed twist when you step on the accelerator. Lexus claims the RX 450h's hybrid system gives the power of a V-8 and the fuel economy of a four cylinder--a not entirely inaccurate statement.

Total power from engine and electric motor is rated at 295 horsepower, a little short of a V-8, while fuel economy gets an EPA-rated 32 mpg city and 28 mpg highway. In our mixed city, freeway, and mountain driving we achieved 27.7 mpg, a figure that many four cylinder cars would have trouble hitting.

Lexus improved its hybrid system for the 2010 model year, using lighter battery, motor, and control module components. At the heart of the system is a planetary gearset, mixing power from the engine and electric motors and relaying it to the front wheels. The RX 450h is also available as an all-wheel-drive vehicle, where it gets an extra electric motor for the rear wheels.

Through the city
In typical full hybrid fashion, the RX 450h glides forward under electric power when you put it in drive. All but the lightest pressure on the accelerator kicks in the gas engine for the extra power the car needs to get up to speed. We like the idea of keeping it running under electric power for as long as possible--it's always pleasing to watch the fuel economy climb--but in city driving it's not really practical. To avoid blocking traffic and frustrated honking from people behind us, we gave it extra throttle when the lights turned green, kicking in the gas engine to get something more than a sedate push. You can drive more economically than we did, but be ready for other drivers to give you the old somersaulting fowl gesture as they pass by.

The RX 450h uses an electric power steering module, but, as in the new RX 350, Lexus tuned it for a little more road feedback than in the previous generation. Where the wheel in the earlier RX could be turned with one finger, the new one gives a satisfying resistance, making you feel like you're controlling the car. But this resistance didn't keep the RX 450h from being very drivable in the crowded urban streets of San Francisco. In fact, with the hybrid system keeping the engine quiet at stop lights, it seemed like an excellent urban vehicle.

Outside of the city, the 2010 RX 450h proved a pampering capsule on the open road, its suspension delivering a smooth ride over all manner of rough pavement. At freeway speeds, the gas engine generally stays on, ready to provide passing acceleration when needed, and explaining why the city fuel economy is better than the highway rating.

We wouldn't normally test out an SUV like we would a sports car, and certainly not a hybrid model, but we did find ourselves late for a meeting, on the wrong side of a coastal mountain range, and so pushed the RX 450h hard over winding roads. Well, not too hard, but enough to get the traction control to quell our speed in a few turns in that intrusive fashion that Lexus road-holding electronics use.

Ignoring good fuel economy practices, we repeatedly punched the accelerator coming out of turns, getting a strong result from the car as it picked up speed. In the turns, the RX 450h didn't wallow particularly, its suspension trying to put it back on an even keel after inertial lean attempted to pull it away from the apex. In all, it showed itself game for this type of driving, it not entirely capable. Understeer was evident entering the turns, and the rear wheels were more obedient followers than active participants.

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