"Having these more stringent tailpipe standards is something that we're already counting on, to be able to achieve those goals. Being able to have those in place quickly is very critical in terms of our ability to reduce emissions from this very important sector."
Washington and Oregon were even part of a lawsuit a few years ago, to try to force the EPA to make a decision on allowing states to set their own tailpipe emissions standards. Macfarlane says it's not just clean air at stake – it's also less dependence on foreign oil, and better gas mileage.
"The reason there's a need for these kind of standards is that the current fleet of motor vehicles sold in America today gets worse gas mileage and emits more greenhouse gases per mile than the Model T's that were sold back in the 1920s."
About half of all the greenhouse gas pollution in Washington is from vehicles. Macfarlane says the next step is a federal "clean car" standard that applies to all states, but that won't go into effect for a few years. In the meantime, the state rules take effect, beginning with cars made in model year 2009.