It's back to school season and chances are, most students are catching the bus. America has a fleet of nearly half a million school buses. Those big yellow vehicles travel nearly 3.5 billion miles each year, emitting millions of tons of greenhouse gases, that's according to school bus fleet dot com. It might be time for the yellow buses to go green. For more on that argument, we spoke to Jason Torchinsky, Senior Editor at Jalopnik.