When that happens, California's newly implemented emissions standards — the toughest in the United States — will be in effect along the entire West Coast from Canada to Mexico.
By 2016, all new cars, sports utility vehicles and light trucks sold in the West Coast states would have to comply with the tougher standards on emissions of greenhouse gases such as carbon dioxide, which are believed to be a leading cause of global warming. The 2016 date was set to give automakers plenty of time to comply with the new standards.
At least six states in the Northeast are also moving to adopt California's new tailpipe standards to reduce greenhouse gas emissions from cars.
It's an environmental squeeze play — with states on the two coasts working to try to force the auto industry to turn out cleaner, more fuel efficient cars, since those states comprise nearly a third of the U.S. car market.
"People realize that having more advanced-technology cars on the road will enhance our oil security and begin to address global warming issues," says Rob Sargent of the Boston-based National Association of State Public Interest Research Groups.
Under the federal Clean Air Act, California is allowed to set pollution standards for cars and trucks that are more stringent than federal standards. Other states can choose either California's standards or the looser federal rules.
Most northeastern states have followed California vehicle emission rules for years, and now those states are making the change to reflect California's latest rules regulating carbon dioxide and other greenhouse gas emissions from vehicles.