Savage and Hyneman collaborated with Professor Kent Johnson, an assistant research engineer at the University of California at Riverside, to cross-examine "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 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."
