According to the American Automobile Association, the average annual cost of driving a car is $8485. Of that amount $7,0095 leaves the community in payments for finance charges, gasoline, insurance, etc. (See graph)

Transit costs the user far less (in Madison, an unlimited ride monthly bus pass is $55 – or $660 a year. That represents an annual savings of more than $7,500 over driving. That number does not including parking which can total more than $120 a month.
Using transit instead of driving keeps those dollars in the community.