Hey Mr. Green,
Do two people in a car produce fewer total emissions per person than one rider on a motorcycle?
--Jason in South Pasadena, California
Motorcycles, being much smaller than cars, can burn way less fuel, and therefore can emit less carbon dioxide. But not all crotch rockets are created equal, so two folks in a car could easily produce less CO2 than one motorcycle rider, depending on the bike's engine size. Honda's 1,832-cubic-centimeter Gold Wing, for instance, gets only an estimated 36 miles per gallon, while its little 108-cc Elite scooter buzzes along at 107 mpg.
Smaller models of many other brands also burn way less fuel than their big brothers.
Pollution-wise, however, many motorcycles are nowhere near as clean as cars, because they are allowed to emit higher levels of such pollutants as nitrogen oxides and hydrocarbons. Even under the EPA's latest standards, a bike can legally gurgle out almost 20 times as much hydrocarbon as a midsize car, while some older bikes can produce 90 times as much. So, if solo commuters would get social and carpool, autos could handily beat many motorcycles.
That said, it's a shame so many Americans, unlike Europeans, still regard motorcycles not as modest, low-impact transportation, but instead as macho lifestyle statements--like Star Motorcycle's 1,700-cc VMAX, advertised as an "iconic beast" and the "ultimate muscle bike." That's the sort of hog the late gonzo journalist Hunter S. Thompson rode with Hell's Angel Sonny Barger at a velocity rivaling that achieved when they blasted Thompson's ashes out of a cannon at his funeral.
So motorcycles have an identity crisis similar to that of bicycles: Just as pedal-powered two-wheelers have yet to be fully liberated from the realm of recreational toys and taken seriously as transportation, motorcycles need to go beyond noise and testosterone to play a bigger role as earth-friendly transport.