Lyric discussion by galaxiaad 

Cover art for Passenger Side lyrics by Wilco

He's gotten his driver's license suspended after a DUI. Either the girl he's interested in has rejected him, or he doesn't have the nerve to ask her out, because he feels frustrated/ashamed at being dependent on others to drive him around. I think the "should've been the driver" part is intended to sound ironically similar to people regretting drunk driving accidents, but is in fact just referring to his lack of success with the girl (because of the DUI). There's definitely some immaturity here.

My Interpretation