Just figured out all my car related expenses on a cost per mile basis. Have found out that, driving less than 15,000 miles/year makes every mile cost about one quarter dollar. Constant 11 cent per mile in gas alone, but about 9 cents in insurance. If I drove more, that might only be 5 cent, but my total cost of gas would be higher. I love the practical uses of math!

Ah but have you done a relative cost analysis versus public transportation?
I was hoping you’d include the relative costs of riding a bike, walking, taxi, bus, mooching off friends, and living as a hermit and never leaving your apartment. Oh and don’t forget the social, emotional, and health related costs of each solution.