How One Diesel Scandal Changed The Engine In Your Car

In the spring of 2014, a Volkswagen Passat drove from Los Angeles to Seattle with a box of lab equipment strapped to the back and a hose clamped over its tailpipe. The car had already passed California's official emissions test, so the West Virginia University team riding along figured they'd get a dull result. But out on the open highway, that Passat was producing around twenty times the nitrogen oxides it had made in the lab. So how did one road trip end up shaping the engine in the car you drive today, even if it runs on gasoline?