Seven car companies have begun selling low-polluting cars in California, where they are called PZEVs, for partial zero-emission vehicles, according to USA Today. They're all normal vehicles - Honda Accord, Toyota Camry, BMW 325 - that look and perform just like their non-PZEV counterparts sold in other states. California car buyers might not even have known they bought low-pollution models, so innocuous are they, USA Today said. California, because of its smog, requires the biggest automakers to sell PZEVs and other low-pollution vehicles to help the state meet federal clean-air standards. The extra cost of PZEV (pronounced PEE-zev) hardware is estimated at $500 a car by automakers and consultants. Whatever the amount, most car companies say it is enough to discourage them from offering PZEVs nationwide. Ford and Toyota are going nationwide, nonetheless, to spread the extra cost of California PZEV hardware over more cars and to earn public relations points for showing environmental concern. Even if other automakers don't follow suit promptly, they'll have to move in that direction as U.S. auto-pollution regulations get progressively stricter starting with '04 models and begin to converge with California's pollution restrictions the next few years, according to USA Today. "It's only a matter of time before essentially all gasoline-fueled passenger cars and light trucks are PZEVs," says Tom Austin of Sierra Research in Sacramento, which studies clean-air issues for government and industry.