City Population Shift Maps

These Day-Night maps are from a Time Magazine November 2007 interactive map feature called One Day in America.  Other cities highlighted are Dallas, San Francisco, Seattle, Boston, Chicago and more.  The feature also included histogram map of traffic delays.  

The maps were created by Joe Lertola, who has some other great stuff posted on his website.

Thanks to justinpobrien for sending me the link in the comments.