Imagine if you kept your feet moving all day. Even in place. You would waste a lot of energy (or lose a lot of weight depending on how you look at it). The latest ad from Buick cleverly depicts just that, while metaphorically showcasing the intuitive start/stop feature that’s just part of the powertrain of the 2012 LaCrosse eAssist. It’s also a big reason why the full-sized vehicle touches 36 miles per gallon on the highway — exactly the same as the smaller and much more basic 2011 Chevy Cruze.