Toyota, General Motors and seven other automakers filed suit on Tuesday to block California's new greenhouse gas regulation, which was approved by the state in its final form in September.
The suit sets up a battle between automakers and Governor Arnold Schwarzenegger, a Republican. Although he is a fan of the Hummer, Schwarzenegger has promised to defend the regulation, which was signed by his Democratic predecessor, Gray Davis.
The regulation -- the first of its kind in North America -- would require automakers to cut by roughly 30 percent the greenhouse gas emissions from cars and trucks sold in the state by the 2016 model year.
The industry is suing in federal court in Fresno contending that California's regulation is pre-empted by Washington's authority to regulate fuel economy. Greenhouse gas emissions from cars and trucks are a function of fuel economy.
"Federal law is designed to ensure a consistent fuel economy pro-gram across the country," said Fred Webber, the chief executive of the Alliance of Automobile Manufacturers, the lobbying group that filed the suit on Tuesday with several car dealers.
In an interview last week, Terry Tamminen, California's Cabinet sec-retary and a top adviser to Schwarzenegger, said the governor "supports the greenhouse gas bill." Tamminen added that the governor had said that "he intended to fight the expected court challenges."
Automakers said on Tuesday that greenhouse gas emissions and fuel economy should be handled by Washington, though the industry has also lobbied vigorously against significant increases in fuel economy standards by Congress.
Largely because of the rise of the sport utility vehicle, the average fuel economy of new vehicles sold in the US has declined since the late 1980s, driving up greenhouse gas emissions and increasing US oil consumption.
"The auto industry is claiming that no action should be taken on the federal level to clean up cars; now they're claiming no action should be taken at the state level," said Daniel Becker, global warming policy director at the Sierra Club.
In a letter to top managers on Tuesday, William Clay Ford Jr, the chairman and chief executive of the Ford Motor Co, said he was still committed to addressing climate change. Ford has been outspoken on the issue in Detroit, and his company has internally laid out a goal to reduce greenhouse gas emissions over a much longer time frame, by 2030.
But "the prospect of 50 different requirements in 50 different states," he said in his letter, "would be nothing short of chaos."
Automakers mainly fear the prospect of two efficiency requirements: one from Sacramento and one from Washington. California already has the unique authority under the federal Clean Air Act to set its own air quality rules, because the state's smog-battling rules predated those of the federal government. Other states have the discretion to choose California's air rules over those of Washington, and seven states in the Northeast, including New York, do so. That means that under the new regulation, a fifth of the US auto market could have far stricter efficiency rules than the rest of the country.
The industry contends that California's new rules would add about US$3,000 to the average cost of a new vehicle. State regulators have said that the added cost would be closer to US$1,000, which would be more than made up for over time by saving fuel.
Automakers have also said they would probably react by restricting their sales of large sport utility vehicles and other inefficient vehicles in California.
In addition to Toyota and General Motors, the other automakers in the alliance that filed the suit are Ford, DaimlerChrysler, BMW, Mazda, Mitsubishi, Porsche and Volkswagen.