On the contrary, there are plenty of proven energy-efficient technologies available, none of which has lacked for publicity or industry backing. A few years ago Renault trotted out a rig that got 121 mpg on the run from Paris to Bordeaux. I'm told the gas mileage record for motorcycles is about 400 mpg, and if you really want to go crazy, a GM subsidiary recently built a solar-powered prototype called Sunraycer that doesn't use any gas at all. On the downside, it seats only one, has no trunk or luggage rack, and barely has room for a pair of fuzzy dice. But hey, life is full of trade-offs.
High mileage is never the result of a single miraculous component, such as a carburetor.
Rather it's the sum of numerous small improvements. Soon to come, it's believed, are ceramic diesel engines using turbochargers and perhaps stratified charge engines that combine the best features of gasoline and diesel technology. While 200mpg is pushing it, the experts think 110mpg cars are within range of current technology. Well, don't rush down to the auto showroom just yet. It may be years, if ever, before the new technology becomes widely available.