The firm's research concluded that more customers pick the Prius over alternatives like the hybrid version of the Honda Civic precisely because the Prius is exclusively -- and identifiably -- a hybrid. While just 36 percent cited fuel economy as a prime motivator for buying a Prius, 57 percent said their main reason was that "it makes a statement about me."

What's more, in focus groups, many Prius buyers admit expecting acclaim from friends and co-workers for making such a socially responsible, planet-saving purchase.

But the satisfaction of some eco-drivers risks swelling to self-righteousness -- like the Prius driver coasting down Highway 101 in Marin County last week with the bumper sticker: "How many lives to the gallon do you get?"

When Arianna Huffington wrote a testimonial to the Prius' ability to reduce foreign oil dependence and called owning one "an act of patriotism," her Huffingtonpost.com site also created a virtual photo album for hybrid owners. Actor/writer Larry David, whose wife is reported to delight in flipping off Hummer drivers from the comfort of her Prius, quipped "I needed something to make me feel smugly superior."

Add to the mix the bitterness some other drivers feel because parking and carpool lane rules don't apply to most hybrid owners, and the hypocrisy of Prius-preening celebrities who prefer to travel on private jets, and even the recent arrest of Al Gore's son, an associate editor of a magazine called Good, who allegedly was speeding at more than 100 mph in a Prius.

The predictable result? Backlash.

An episode of the raunchy and politically incorrect cartoon "South Park" took merciless aim. One character purchases a "Toyunda Pious" and tries to harangue the rest of the town into converting, before giving up and fleeing to be among fellow hybrid lovers in San Francisco.

Soon the folks in South Park see the light and switch to hybrids as well, only to discover that although smog rates are plummeting, hybrid drivers are rampantly spewing a toxic gas called "smug" -- leaving South Park with a smug pollution level second only to San Francisco. Then, oppressive smug clouds above both collide with a third smug cloud emitted by George Clooney's Oscar speech, creating a "perfect storm."

Ultimately people vow to eschew hybrids regardless of their virtue: the prospect of driving them sans smugness is "simply too much to ask."

Right-wing politicos exude a similar caustic cynicism toward Prius owners, whom they seem to regard as stand-in punching bags for their old nemesis Gore.

Complaining about liberal greenies motivated by "glamour reasons" to buy Priuses, Rush Limbaugh declared "I wouldn't be caught dead in one of those things. They look ugly to boot. I mean, part of the intrigue of these things is they've tried to design these things as a car that the Jetsons would drive. These liberals think they're ahead of the game on these things, and they're just suckers."

Among the contented Prius owners are Bob Stern, president of the Center for Governmental Studies in Los Angeles, his wife and his son. Their Priuses are colored red, white and blue.

"I think there's real resentment about us being able to use the carpool lanes and ignore the meters," he acknowledged. "If you're in the carpool lane in a Prius -- and most of us don't drive 103 miles an hour -- people will tailgate you and flash you. ...

"So sometimes when you're sitting in traffic near a big SUV or Hummer and you can't even see around them, you do think to yourself, 'At least I'm getting three times the gas mileage they're getting.' Is that smug?"

As online chat rooms percolate with snarky attacks on and defenses of not only the Prius but its owners as well, Prius Progressives may be on their way to becoming a punch-line, an archetype -- like Hummer drivers (narcissistic macho wannabes), Bimmer drivers (materialistic corporate strivers) and Volvo drivers (earnestly self-absorbed yuppies) before them.

All these labels, of course, are simplistic -- even the ones that contain grains of truth.

So what, really, if Prius owners took image into account in buying a car? Exactly who doesn't? The power train of the entire automobile industry rests on the premise that advertisers ably seduce us into the fantasy "we are what we drive."

Even Prius Progressives who freely admit buying their cars to make a statement dispute the notion that it makes them poseurs.

"I'm doing a small but important thing to help make my country more energy independent and clear the air," said Prius driver Kay Smith of Vallejo. "If what I drive catches someone's attention and makes them rethink their choices, then yes, I feel good about that. It's not that I have all the answers. We all can learn from each other, bit by bit by bit."