California is known around the world as a leader in promoting innovative and environment friendly vehicle policies. If you have any doubt about that, check out the Union of Concerned Scientists' summary of California's role in promoting cleaner vehicles. California has every incentive to maintain this leadership position, UCS points out, because California is one of the 10 largest carbon emitters worldwide and represents 10% of the nation's new vehicle market.
In an earlier post, John Shore explained the connection between vehicle weight and MPG. Many advances in fuel efficiency have gone towards supporting the steady increase in vehicle weight instead of lowering MPG.
A couple of years ago, Andy Bowers of Slate exposed a hidden way for California to encourage lighter, cleaner vehicles. He noticed street signs in his neighborhood prohibiting vehicles over 6,000 pounds, and realized the following:
By weighing in at more than 6,000 pounds, big SUVs are prohibited on thousands of miles of road in California. Cities across the state—including San Francisco, Los Angeles, Pasadena, and Santa Monica—use the 3-ton cutoff for many or nearly all of their residential streets. State law gives them the ability to do this for very straightforward reasons: The heavier the vehicle, the more it chews up the roads, endangers pedestrians and smaller vehicles, and makes noise.
This isn't an arbitrary weight limit. 6,000 pounds has long been a recognized dividing line between light and heavy trucks. (For example, the Clean Air Act defines "heavy duty vehicle" as a truck with a gross vehicle weight "in excess of six thousand pounds.")
He lists several of the vehicles that exceed that limit, including:
The Chevy Suburban and Tahoe, the Range Rover, the GMC Yukon, the Toyota Land Cruiser and Sequoia, the Lincoln Navigator, the Mercedes M Class, the Porsche Cayenne S, and the Dodge Ram 1500 pickup (with optional Hemi). What about the Hummer, you ask? Hasta la vista, baby!
SUV owners happily use their vehicle's 6,000+ lb gross vehicle weight rating (GVWR) to qualify them for large federal and state tax breaks. I'm sure they wouldn't be so happy if California started enforcing the fines associated with the (admittedly unintentional) ban. But for California, it would be another front-of-the-pack attempt to encourage more fuel-efficient, clean vehicles!