Using portable emissions equipment, a wide sampling of cars and bikes from the 1980s, 1990s and 2000s and with the help of Dr. Kent Johnson of UC Riverside, the Mythbusters team claims they proved motorcycles are dirtier than cars. Doing so meant gathering data in real-world driving conditions along a 75-percent freeway, 25-percent city driving loop in and on the vehicles from different eras. The results of that test proved one thing that everyone should already know: motorcycles use less fuel than cars. They also produce less carbon dioxide than cars, which accounts for 90 percent of a vehicle's emissions.
Autoblog
See also:
gadgetsdaily, Mythbusters answers which is greener, cars or motorcycles?
