2010 Toyota Prius

No shoes were flung when the 2010 Toyota Prius debuted at the recent Detroit auto show. Considering the grim mood in the Motor City - with domestic automakers on death watch and frozen credit paralyzing sales - and the fact that a gallon of gas costs little more than a can of beer, that's remarkable. Detroit was hardly the opportune place for a fuel-scrimping, technically advanced Asian import to bow. Then again, consider the Latin meaning of the word Prius: to go before. Defying skeptics is this car's cause. The Prius's mission has always been venturing ahead of the gas-saving, earth-hugging curve.

Toyota calls this the third generation of the Prius (not counting one sold in Japan from 1997 to 2000 but never imported here), but the gist of the world's best-selling gas-electric hybrid hasn't changed an iota. It rides on the same 106.3-inch wheelbase as its predecessor, and its external dimensions are longer, lower, and wider by smidgens. The fresh but still nerdy-looking skin smites the wind with a drag coefficient trimmed from 0.26 to 0.25. The front wheels are again energized by a compound powertrain consisting of one four-cylinder engine, two motor/generators, one planetary gearbox, and a nickel-metal-hydride battery pack.

The rumored plug-in lithium-ion batteries are a no-show for now, yet Toyota engineers overhauled the rest of the Prius's propulsion system. The DOHC sixteen-valve I-4 engine grows from 1.5 to 1.8 liters in displacement, upping peak output from 76 to 98 hp at 5200 rpm. One carryover feature is the use of the Atkinson cycle, a delayed intake-valve closing arrangement that yields a longer expansion stroke and reduced fuel consumption. The most notable engine innovation is the elimination of belts under the hood; all accessory equipment (A/C compressor, coolant pump, power-steering pump) is now directly driven by the engine or by an electric motor.

GREEN: 2010 Lexus RX450h

The RX is the best-selling Lexus, and one in five sold is the hybrid version. It's no surprise, then, that with the new third-generation RX - the second to have a hybrid powertrain - Lexus is treading very carefully.

The design is a careful evolution, both inside and out. The car is slightly longer and wider but manages to look sleeker than before. The interior retains the traditional Lexus virtues of comfort (on even bigger, cushier seats) and refinement (with available semi-aniline leather for a still more luxurious feel). Lexus has joined the Germans by adopting an iDrive-style controller instead of a touch screen for its optional navigation system. But rather than a knob you twist and push, the Lexus control (called Remote Touch) works more like a joystick that you move from side to side or forward and back, and then make a selection by pressing buttons on the side of the unit. It takes some getting used to.

Other new options don't require a learning curve, such as the head-up display and the curb-view camera; the latter is located in the right-side mirror, and at low speeds it shows an image of what's alongside the car. The hybrid model supplements its previous ECO indicator, which lights up when you're driving efficiently, with a selectable ECO mode, which changes the responsiveness of the throttle and instructs the climate control to use the A/C compressor more judiciously. There's also an EV mode, which extends the threshold before the engine starts, up to a still-modest 8 to 10 mph.

The changes aren't dramatic, but Lexus has given its cushy suburban hybrid a slightly greener tinge. Lexus engineers identify four elements that underpin the brand's hybrids: performance, quiet refinement, low emissions, and fuel economy. In this redesign, the latter received the most emphasis.