Even the Big Three auto manufacturers in Detroit are rushing to replace their gas-guzzling SUVs with smaller cars, and developing new hybrids and electric cars.Toyota has announced plans to produce its popular Prius in the U.S. to help keep up with demand and reduce costs, while Honda is about to launch its first hybrid-only car. (Tangentially, Nissan's dealers now have so many Titan pickups sitting around unsold that Nissan is sending them solar chargers to keep the batteries from dying out of disuse!)

And the message at the Plug-In 2008 conference was that 100 MPG cars are just around the corner. If have a hybrid and you're willing to break your warranty, you could already have a 100 MPG car. But short of major modifications, you'll probably have to wait a couple years for an off-the-lot version.

In GOOD Magazine, Cliff Kuang says we should forget about a 100 MPG car for now anyway: "If you really think about it, the 100-miles-per-gallon innovation isn't as immediately effective as making a simple switch from a Suburban to a Civic. Just do the math: If you raise a guzzler's fuel efficiency from 15 miles per gallon to 35 miles per gallon, you save almost four gallons per 100 miles. But boost a fairly efficient car from 35 mpg to 100 mpg, and you save less than two gallons in the same distance. More importantly, the technology for all cars to reach 35 mpg is already here. The same innovations that in the last 30 years have made family cars into muscle cars can be easily deployed to save gas rather than boost performance."