After Bob Texeira converted his Benz to run on Wesson oil (or Mazola, canola, soy oil, you name it), he slapped a bumpersticker on the back to advertise the achievement: "Powered by 100 percent vegetable oil." Then the cops pulled him over. As Marketplace explains
Texiera was breaking a number of obscure laws. First, he owed the state a $2,500 bond to run his car on vegetable oil. And he owed a thousand dollars for neglecting to pay monthly state road taxes normally levied on gasoline. Federal penalties were involved, too.