While cars may be the least subsidized in terms of monies paid from the government for infrastructure projects, we have to consider the whole cost to society of any form of transportation. I can't claim to be an expert in this area, but I do know that there are many externalized costs to anything that uses energy; the impact on the environment affects our collective health and the long-term health of our planet. Depending on the economist and what all they include, the actual cost of a gallon of gasoline to society (purchase price + cost of mitigation of impacts caused by said gallon of gas) is said to be somewhere between $20 and $60 (I will try to find the source of these numbers for you if interested-they came from some readings I did in one of my college classes).

Of course, this doesn't just affect cars, but the externalized costs are proportional to how much fuel a vehicle uses. Air transport, under this model, is hugely subsidized as well (more than almost any car/truck/SUV), while an energy-efficient form of transportation such as rail, is much less.

Of course, if all you care about is your cost/savings, these numbers don't really matter. I trust though, that those frequenting this forum care about a wider variety of issues than would the average, short-sighted consumer.