Earlier today, President Obama announced national rules for automobile emissions and mileage standards. Though these rules won't take effect until 2012, it's a good start.
The new mileage standard will be 35.5 miles per gallon, a rise from the current rule of 25. One of the issues with regulating mileage standards is that each state determines its own. California currently has a mileage standard of about 35.5, with a few states (and the District of Columbia!) planning to adopt California's standards. Now, with a national standard, this will be unnecessary.
It is supported by both environmentalists (for obvious reasons) and the auto industry, which is currently planning its business strategy.
Read more about this plan from the New York Times or from New York Magazine, which offers a wide range of opinions.
[UPDATE: 5/20, the NYT's editorial board endorses this act in "The Earth Wins One."]