40 MPG with today's technology would mean we'd all have to drive hybrid cars like the Prius, conventional gasoline cars with very tiny engines (think 3 cyl. Geo Metro), or small diesels, like the VW TDI. While these cars will suffice for many people, I don't think most Americans would be happy with them. 40 MPG would mean no pickups or SUV's, and where I live, those account for 75% of the vehicles on the road. I think the answer lies in alternative fuels, such as CNG or hydrogen. Unfortunately, we don't have a lot of natural gas reserves, which would allow us to make the easiest conversion to non-petroleum powered vehicles. Electric vehicles aren't really practical until someone develops a truly long range battery pack. Hydrogen shows promise, but its going to take years of development to get the vehicles and the infrastructure in place. And remember, the big boys in the oil companies like their fat salaries and aren't enthusastic about the country weaning itself of its oil dependence.
