That kind of thing (laws and regs already passed) is also most of what has gotten us to near-compliance with AB32. OTOH, the higher gas mileage requirement is one of the things contributing to under-funding of highway maintenance (burn less fuel per mile than average = contribute less in gas tax to maintaining the road). I've been wondering if anybody has figured out what the break-even points are for covering road damage/maintenance per vehicle for various weight classes, and what combination of fuel and other (for vehicles that don't burn taxed fuel) taxes would be required to produce that. Not a railroad issue, I know, so off topic, but since that was a (poorly-described and even more poorly-implemented) driver of the SB350 process it's worth a thought.