Dean Karnopp, professor of mechanical engineering at UC Davis, has more than 30 years experience with thin, three-wheeled vehicles that automatically tilt round corners. Tilting allows three-wheelers (or TTW) to combine freeway performance with gas mileage ranging from 90 to 140 miles per gallon, Karnopp said. Because they can be made one person wide, like a motorbike, TTWs reduce parking problems and by using narrow, dedicated lanes could reduce freeway congestion. Unlike conventional motorcycles, which fall over if they lose traction, thin TTWs can remain stable in a skid. They are fully enclosed and can be fitted with features such as multiple air bags to bring safety to race-car standards. Karnopp believes tilting thin vehicles are a practical alternative, using established technology, to all-electric vehicles, gas-electric hybrids and fuel cell vehicles as a solution to pollution and transportation problems. These vehicles are already being built by companies in California and elsewhere, he said.