When California allowed solo occupants of hybrid cars to use carpool lanes last year, many thought they were merging onto a narrow strip of car culture heaven.
But increasingly, hybrid owners say they feel like the victims of road rage.
Carpoolers accuse them of driving too slowly in order to maximize their fuel efficiency, and of clogging diamond lanes that were once clear.
Hybrid motorists even have a term for the ill will: "Prius backlash."
"There's a mentality out there that we're a bunch of liberal hippies or we're trying to make some statement on the environment," said Travis Ruff, a real estate agent from Newbury Park who drives a Toyota Prius. "People are a lot less friendly than when I drove a Mercedes."
Caltrans, which has issued carpool-lane stickers for about 50,000 hybrid cars, plans to study the effect of hybrids on carpool lanes, starting with the 405, 210 and 105 freeways.
"There's not enough excess capacity to absorb the hybrids," said James Moore, director of USC's transportation engineering program. "I think the foreseeable outcome here is that the congestion advantage we traditionally attribute to [carpool] lanes will disappear."
A debate over carpool-lane congestion also is occurring in Virginia, which like California allows solo hybrid drivers to use the lanes. Last month, the Virginia Legislature placed curbs on hybrid drivers using the lanes in peak hours, requiring three or more people per vehicle, except for those grandfathered in.
The California Legislature approved the hybrids in carpool lanes as a way of encouraging the use of the low-emission, high-fuel-economy vehicles.
The law grants carpool-lane access to hybrids that get at least 45 mpg. So far, only the Toyota Prius, Honda Civic and Honda Insight qualify. The vehicles use small internal-combustion engines in combination with electric motors to increase gas mileage and reduce air pollution. Larger hybrid SUVs and luxury sedans with solo drivers are not allowed in carpool lanes.
From the beginning, the law has prompted complaints from carpoolers. But in recent months the criticism has grown louder as carpoolers accuse hybrid drivers of clogging the lanes, also known as high-occupancy vehicle lanes.
"Prius drivers tend to drive slower, and it makes the HOV lanes slower," said Theresa Poprac, who commutes on the 405 Freeway every morning from her home near Los Angeles International Airport to her job as head of sales for an educational software company in Costa Mesa.
The chatter is more biting in Internet car chat rooms, where some carpoolers have declared themselves "hybrid haters."
"These [drivers] barely go 65 mph and allow no one to pass them on the right," fumed one driver on the Edmunds.com car town hall. "Talk about road rage!"
"Go with the flow, or get the heck outta the way!!!," wrote another in support.
Beyond the driving habits of hybrid users, carpoolers gripe that all those Priuses are beginning to clog the diamond lanes. On some freeways, it's clear hybrid drivers are shaving substantial minutes off their commute by going in the carpool lane. But on others, that doesn't appear to be the case.
Mar Vista resident and hybrid owner Jan Strnand, who often drives the 405 Freeway to Carson, said he has not been impressed with the program.
"Much of the time, the HOV lanes and standard lanes are going at the same rates, so there's no advantage," said Strnand, a television writer. "You do the math.... How many can you add [to the carpool lane] before it's more of a deterrent than it is a help?"
Assemblywoman Fran Pavley (D-Agoura Hills), who proposed the hybrid carpool-lane bill, said most hybrid users tell her they love the privilege. Still, she acknowledged that on some freeways, the time saved during rush hour has been a question -- something the state study will seek to sort out.
But the Prius backlash isn't confined to California's carpool lanes. On a recent episode of Comedy Central's "South Park," one of the cartoon characters persuades everyone in town to buy a hybrid car. But hybrids end up creating their own air pollution. Not smog. "Smug."