I see it as basically Malthusian: people will keep driving until it is so unpleasant that they don't want to do it any more. The tipping point for most people

I see it as basically Malthusian: people will keep driving until it is so unpleasant that they don't want to do it any more. The tipping point for most people is around 45 minutes. Here's a book with a footnote that mentions that the same 45-minute rule applies worldwide and though out history: http://books.google.com/books?id=uuqIA-ce1CoC&pg=PA408&lpg=PA408&dq=ancient+romans+commute+45+minutes&source=bl&ots=W_4--bDOo5&sig=uNYXKSxadR3pUeZ3epHuKgvI0GQ&hl=en&sa=X&ei=xLGxU-vIHoiTqgaUhIDYDQ&ved=0CDEQ6AEwAg#v=onepage&q=ancient%20romans%20commute%2045%20minutes&f=false http://books.google.com/books?id=uuqIA-ce1CoC&pg=PA408&lpg=P...