Adam Savage

In a revelation sure to disquiet Vespa-riding urbanites and independent streamliner engineers, a study conducted in conjunction with a recent episode of “Mythbusters,” the Discovery Channel program, found that cars were greener than motorcycles.

The episode aired on Wednesday and featured the segment “Bike vs. Car,” in which three cars and three motorcycles, each built in either the 1980s, ’90s or ’00s, were fitted with tailpipe probes that measured the carbon dioxide and carbon monoxide emissions of each vehicle over a closed course in Alameda County, Calif.

Though the show’s hosts, Adam Savage and Jamie Hyneman, did not disclose the makes and models of the vehicles, the 1980s car bore a strong resemblance to an Olds Cutlass Ciera (but we wouldn’t rule out a Buick Century), the ’90s car clearly was a Honda Accord and the ’00s car a Ford Taurus or Mercury Sable.

Data retrieved from the tailpipe probes and monitors mounted to the vehicles’ engine control units was interpreted by Prof. Kent Johnson, an assistant research engineer at the University of California at Riverside, who also analyzed the vehicles’ emissions of hydrocarbons and nitric oxide.

In the end, Mr. Johnson observed that while the motorcycles burned fuel more efficiently and produced lower levels of carbon dioxide than the cars, the noxious pollutants generated by the bikes exceeded the levels generated by the cars. Insofar as the hosts sought to determine the greenest mode of transport, the car won by virtue of its lower pollution profile.