If you want to know how green your new car is, just read the label.

The California secretary of state recently signed a regulation requiring that -- no later than Jan. 1, 2009 -- all new cars sold in the state will have a label explaining their impact on the environment. The labels could be seen on vehicles as early as July and will be prominent on all vehicles beginning in model year 2009.

The label will provide consumers with the information they will need to choose a cleaner-burning car or light truck; automakers will be required to furnish that information to the Environmental Protection Agency.

Under the new system, the label will show two scores: One for smog-forming emissions (a smog score), the other for carbon dioxide (a global warming score). The two scores will be graded on a scale of 1-10, with more fuel-efficient and clean-burning vehicles scoring higher scores as they will have less impact on the environment. The smog index label has been used in California since 1998.

Most average new cars will score five on both scales, but a more fuel-efficient vehicle, like Toyota's Prius, could receive 9-10 points, while a less fuel-efficient vehicle, like Dodge's Grand Caravan, could get only 2-3 points.

This label will give consumers the information they need to choose a vehicle that will save gas, reduce greenhouse gas emissions and fight smog.

The global warming score will be the first notification of any kind to be required on new U.S. vehicles that directly connects carbon dioxide emissions with global warming.

A number of other states are interested in adopting California's automobile emissions standards. They include Arizona, Colorado, Connecticut, Florida, Maine, Maryland, Massachusetts, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Utah, Vermont and Washington.