This is an excerpt from EERE Network News, a weekly electronic newsletter.

July 24, 2002

New California Law to Set Greenhouse Gas Limits on Passenger Vehicles

California Governor Gray Davis signed a bill into law on July 22nd that will set limits on greenhouse gas emissions from passenger vehicles sold in the state. Assembly Bill 1493 requires the California Air Resources Board (ARB) to develop greenhouse gas emissions standards for passenger vehicles starting with model year 2009. The ARB has until the end of 2004 to develop and adopt regulations that "achieve the maximum feasible and cost-effective reduction of greenhouse gas emissions" from passenger vehicles. No specific reduction guidelines are included in the legislation.

Since greenhouse gas emissions are directly related to fuel efficiency, the new law will, in effect, set de facto mileage standards for vehicles sold in the state. Until the ARB develops its regulations, though, it's impossible to judge the impact of the law. The standards will apply to automakers' fleet averages, rather than individual vehicles, and automakers will be able to partially achieve the standards by reducing pollution from non-vehicular sources, including their factories. See the Governor's press release as well as the full text of the bill.

California has the unique ability to set vehicle emissions standards because the ARB existed prior to the Clean Air Act of 1970. That law allowed the ARB to continue to enact tougher vehicle emissions standards than federal law. Other states are allowed to either follow federal law or enact California's regulations. Since other states (mostly in the Northeast) have enacted previous California emissions standards, they may also follow California in enacting greenhouse gas emissions standards.

One recent example of the ARB taking the lead occurred in June, when the board passed new, tough standards for emissions of fine particles known as particulates. See the ARB press release.