An interesting row is brewing in California, according to the Los Angeles Times. Owners of hybrid cars began applying for $US8 decals on Thursday that will allow them to drive solo in carpool lanes but the state says only three hybrids — the Honda Civic, Honda Insight and Toyota Prius — will be allowed.

That leaves four others on the market, the Honda Accord, Toyota Highlander, Lexus RX 400h and Ford Escape, off the list, the paper said, adding that Ford, in the midst of a publicity campaign touting its hybrids as a symbol of its environmental commitment, is not happy.

"The US Congress determined the formula for hybrid vehicles in [carpool] lanes with single occupants, and in that law, the Ford Escape hybrid is equal to the Toyota Prius," Mike Moran, a Ford spokesman in Washington, DC, told the LA Times, adding: "It's not about picking certain cars and excluding others."

The paper said the national highway bill that President Bush signed into law on Wednesday allows states to let hybrids into carpool lanes but California passed a law last year that sets stricter standards than the national standards for fuel economy and emissions.

"Rather than follow the federal requirement, we decided that cleaner cars should be allowed in," Gennet Paauwe, a spokeswoman for the state's Air Resources Board told the Los Angeles Times. "We've always had more advanced air pollution measures here because of the particular challenges we face."

The report said California's effort to push cleaner, high-mileage cars is running up against the auto industry's strategy of using hybrid technology in larger cars and SUVs. Automakers are rushing to add more hybrids in the next two years, including other models from Lexus and Ford, as well as vehicles from Saturn, Nissan and Chevrolet, but few, if any, of those new models will make the cut to get into the state's 1,112 miles of carpool lanes.

"I think people don't necessarily buy vehicles because they're allowed in the carpool lane as a solo driver," Paauwe told the newspaper. "But the carpool lane law is an incentive to buy hybrids. While people may be upset that they can't drive solo as others can, there will probably be further introductions of other types of vehicles that will qualify in the future."

Despite the strict rules, most of the 57,000 currently registered hybrid cars in the state will be allowed in the diamond lanes, Paauwe told the Los Angeles Times.

The paper added that California law grants carpool access to hybrids that are the cleanest-running in their class and get at least 45 miles to the [US] gallon.

The LA Times noted that federal hybrid provision applies nationwide and requires the US Environmental Protection Agency to define what an energy-efficient, low-emissions hybrid vehicle is within 180 days - California would have to change its standards only if the EPA decides on mileage requirements that are higher than the state's, which most officials doubt will happen.

Although eligible hybrid owners could start receiving stickers in the coming weeks, officials expect it will be several months before solo drivers can use the carpool lanes, the paper said, noting that Virginia is the only other state to grant carpool access to solo motorists in hybrid vehicles.