There is an interesting Planet Money episode about this: http://www.npr.org/sections/money/2015/06/05/412240643/episode-630-free-parking http://www.npr.org/sect

There is an interesting Planet Money episode about this: http://www.npr.org/sections/money/2015/06/05/412240643/episode-630-free-parking http://www.npr.org/sections/money/2015/06/05/412240643/episo...