Originally Posted by
alhedges
If you click through, you'll see they aren't really talking about how much it costs to own a car. Depreciation is not an "expense" of owning a car any more than it is an expense of owning a bike. What AAA is saying is: (1) if you buy a new car; (2) with a 5 year loan at 6%; and (3) replace that car every five years with another new car and another new car loan; then your costs will be as described in the article.
They don't address what happens if you buy a used car, or if you buy a new car and keep it for more than 5 years.
It's interesting information, and close to the IRS number (although the IRS just uses one number), but it only applies to a particular style of ownership.
Which figures you use depends on the purpose for using the figures.
If you're trying to compute your own personal costs and depreciation, then input your own figures. Use one of the Internet calculators that will have you fill out a form, then come up with annualized and per mile figures. Your new Porsche costs more than a dollar a mile. His 18 year old civic runs on French fry oil and costs eight cents a mile. These are interesting figures, but they speak only to the individuals involved.
if you're using the figures in a more general way, you need some aggregated data, which is what AAA provides. Most often in a forum discussion, the participants begin with general questions and figures: what amount does the average American spend on his/her car? How much can people save, on average, if they get rid of their average car? This is the main reason I highly recommend the AAA figures at least as a springboard for our discussions here. (Other reasons I like AAA is that they know the topic very well, and they are unlikely to be prejudiced against car ownership.)