What makes it a "hybrid" is its powertrain -- the Hybrid Synergy Drive System -- that tandems a small and high-tech 1.5-liter gasoline engine (76 horsepower) with an electric motor with peak output of 50 kilowatts (67 horsepower) and a whopping 295 pound-feet of torque.
The system's computers and controllers blend the output of both power sources for optimum efficiency so that, for instance, in stop-and-go traffic the car often runs on electric power stored in its 202-volt nickel-metal-hydride battery. At cruising speeds, the engine output does double duty, driving the front wheels while also turning a generator, whose voltage then powers the electric assist motor. Under heavy acceleration, power from the battery comes online too. The total output of 143 horsepower is enough to accelerate the Prius from zero to 60 mph in about 10 seconds.
The Prius employs a continuously variable transmission -- no stepped gearing -- so that a foot-on-the-floor maneuver produces only a supple and drama-free gathering of speed and a whirring tenor engine note. I drove the car for a week in freeway traffic and it was quite willing until about 75 mph, above which I had to go to the whip to accelerate.
Dynamically, the car is about what you'd expect from an economy car on 15-inch tires. Competent and agile enough to get out of its own way -- independent strut suspension is used up front, while a torsion beam holds up the rear -- the Prius has a light and reactive feel in its power-assisted rack-and-pinion steering and secure assurance in the front-disc/rear-drum brakes with ABS assist. But this is an earnest commuting appliance, albeit one with more than 370 engineering patents to its credit.
You never plug in the Prius. During braking, the electric motor becomes a generator that recharges the battery, thereby recovering kinetic energy that would otherwise be lost as heat in the brakes. If the battery levels get low, the gas engine is summoned to top off the electrons. You can keep up with all this activity on two dash-mounted LCD displays: one, a flowchart, the other, a bar graph indicating recovered kilowatts and other arcana of fuel efficiency.
Most consumers, I suspect, will watch the graphs for a day or so and then flip over to the audio or climate displays, with the peace of mind that comes with knowing they are part of the solution, not the problem.
In fact, it is not the Prius' stark differences -- its fetishizing of thermodynamics -- that make the car marketable, but its sameness, the transparency of the hybrid system. The car uses an electronic key -- a small plastic module that slips into a receptacle on the dash -- that activates the start button on the dash. Put your foot on the brake and press the button; it takes about a second for the car's computers to boot up the instrument display, located near the leading edge of the windshield. The gearshift is a joystick-like unit on the dash, behind and to the right of the steering wheel. Put it in drive or reverse. The park position is engaged by a push button above the gearshift.
There is very little to remind you that the Prius is different from any other economy family car, and quite a lot to suggest it is, in fact, a commuter with upscale aspirations. Standard equipment includes anti-skid brakes and traction control; keyless entry; power windows and locks; heated side mirrors; steering-wheel-mounted audio and climate controls; alloy wheels; CD player; and the multi-function LCD display.
The options list includes high-end blandishments like a navigation system; six-disc CD changer; stability control; and curtain and side-impact air bags. The Prius would be a nifty family ride even without the virtue-intensive powertrain.
But how's this for an incentive: The dead governor walking, Gray Davis, has asked the federal government to grant the Prius -- which is a super-ultra-low-emissions vehicle according to the California Air Resources Board -- an exemption allowing solo drivers to use the car pool lanes on California freeways. A decision from the Department of Transportation is pending.
Given that the world trembles on the edge of fossil-fueled disaster -- from the Mideast to the melting ice caps -- it's hard not to see the Prius as anything less than a manifesto (the term revolutionaries once used for a "vision statement"). Lamentably, even as Toyota leads the way in hybrid powertrains, it is increasing its production of gas-thirsty sport utility vehicles for the American market.
But Toyota is pouring marvelous amounts of its treasure into efficiency research, and its achievements in mass-production hybrid technology haven't precluded work in other directions. The company has a project with UC Davis and UC Irvine to develop fuel-cell technology and infrastructure. By year's end it will have leased six of its experimental fuel-cell vehicles to the universities and given millions to fund research just in California.