Selecting three motorcycles and three cars that represented popular models from the '80s, '90s and '00s, they put the six vehicles through a 30-minute, 20-mile course. Seventy-five percent was freeway driving; the other 25 percent was in the city. Savage drove the three cars. Hyneman trailed him at speed on each of the three bikes. None of the vehicles' makes and models were disclosed.
All of the vehicles were equipped with portable emissions-measuring systems that took exhaust gases from a probe in the tailpipe and engine information from the engine control unit. The devices determined the vehicles' fuel economy and emissions profiles while the vehicles were running on the real-world course in California's Alameda County earlier this year.