That 50-cent per mile rate is always subject to debate. If you have an expensive new car and drive it less, you are still paying for the car and the financing. But by driving it less, you can extend the life of the car and thus amortize its cost over many more years. Or by not driving so much, you can get by with an older car that doesn’t cost as much. There are many ways to figure out the cost of driving other than AAA. Here’s a web site that allows you to plug in your own information and figure it out. You might be surprised: http://www.commutesolutions.org/calc.htm

The only person responsible for your commute time is yourself. I don’t know any businesses that pay you while you commute.

For example, say it takes me 30 minutes to drive/park/get to work and an hour to bike/park/get to work. Also, assume I make $20 an hour. You are therefore taking $20/day (to and from work) of productivity away, which decreases tax revenue and ultimately reduces my pre-tax personal income. Obviously, this assumes that I would be paid for the extra hour of work–but most people are paid overtime, have second jobs, or value their time equivalently. Moreover, that is real money, not a fictional depreciation rate set by the IRS on a car, to which most people can’t lay claim.