An Earth Day Twitter poll: When will it be socially unacceptable to drive a car with a tailpipe?

Exhaust emissions from tailpipe [photo: Simone Ramella, 2005, used under Creative Commons 2.0]Every year, as Earth Day rolls around, we survey the automotive landscape looking for progress in the industry's efforts to reduce emissions and limit global warming. We've identified a lot of progress recently. More than a dozen new electric models are set to go on sale in the coming year, and sales of plug-in models more than doubled in the past...