Nationally, miles driven went down only four times in the last century of American motoring:

1. The Great Depression (people couldn't afford it)
2. World War II (rationing of gas and tires)
3. OPEC oil embargo (actual gas shortage)
4. 2008 ($4/gallon gas)

Every other year, miles driven went up, compared to the year before. If you think about it, that's a mind-boggling statistic.