- The number of drivers has increased 3 times as fast as the increase in population...the number of
household vehicles has increased 6 times as fast. (hooray for the
3 car garage).
By the way, this means there are
approximately 500 million gas powered vehicles in the US.
- The number of highway miles driven by Americans is increasing at 2-3% a year.
Men spend an average of 81 minutes a day behind the wheel, while women spend 64 minutes a day
this is more time than we spend eating and twice as much time as we spend with our children
Energy costs of transporting one ton of material one kilometer:
Amercians spend a large fraction of their dollars on transportation: 
Most of this is tied up to our requirement to have a personal vehicle.
And transportation costs are the main economic hardship amoung lower income groups.
And, of course, America is a big country, full of transportation hogs.
Transport costs depend critically on degree of urban sprawl and commuting patterns and mass transit choices.
And spending patterns vary considerably:
