The 55 cents a mile is for an "average" car, with "average" mileage driven an "average" number of miles per year. The problem is that cars don't depreciate just on mileage, but on age too.

So dramatically increasing the number of miles you drive per year reduces the actual total cost per mile. Using fleet management services and having deals directly with the manufacturer, as well as buying in bulk will generate huge savings, particularly since you almost wipe out the dealer fee.