fuel efficiency v. emissions quality

(PROEric Arnold)

Why Did Volkswagen Only Rig Emissions Systems On Diesel Cars?

Volkswagen has admitted to rigging the emissions control systems on 11 million diesel cars over the last seven years, but those only represent a fraction of all the vehicles produced by VW during that time. Why did the carmaker only choose to tinker with its diesel vehicles instead of the larger number of gasoline cars? And how do we know VW didn’t mess with these vehicles? [More]