14½ years of car ownership

This is an exploration of the cost of owning a car. I purchased my car at the end of 2001 and have always kept fairly meticulous financial records. In April of 2016, I exported all transactions related to my car to see what insights might lie in the data. Behold!


# The big picture

I own a 2002 Acura RSX, Type S, which is the sporty 6-speed version with a slightly larger engine than the standard trim (oh, and also a sweet 6-disc CD changer in the dash, right above the cassette deck).

Purchase price
Other expenses
Total mileage
Cost per mile

Below is a break down of expenses by category. Perhaps unsurprisingly, I have spent more on a place to leave my car sitting unused than I have on purchasing it. Parking makes up 34% of all car expenses.


According to the D.O.T., the cost of owning a car in 2014 was $0.58 per mile. At $1.27, I am well above that. My fixed costs (comprised of insurance, registration, and the purchase itself) are $-, compared to the national average of $0.41. The majority of my costs above the standard are from the parking, which the D.O.T. does not account for at all — free parking is a basic civil right after all.[1]

Category Average My cost
Fuel $0.11 $-
Service $0.06 $-
Fixed $0.41 $-
Parking n/a $-
Other n/a $-

# Amortized costs

I was fortunate to have saved up enough money to pay for my car up front, so my total costs do not include any interest on a loan. Given that, I was interested in seeing how the cost amortized over time.

Below is a chart of the cost per month along with the amortized cost to date. As you can see, the cost looks to be approaching about $550 a month, which is a lot, given how little I actually drive.


# Fuel efficiency (or lack thereof)

For a “sport” car manufactured in the early 2000s, my car is decently fuel-efficient, but because of my driving patterns — lots of city driving with an occasional longer drive out of town — my actual efficiency has varied wildly. The EPA estimated 21 mpg in the city and 28 mpg on the highway, but I have recorded mileage per gallon as low as 17 and as high as 30. The low was a full tank of stop-and-go city driving, and the 30 was using cruise control on the highway, probably with a tail wind.

I also have a roof rack on top, which definitely lowers the fuel efficiency, though differently for highway and city driving and depending on whether the rack is loaded with bikes or not. A study recently came out that estimates an 8-25% fuel consumption penalty for the rack. Perhaps a more accurate average fuel consumption for me is about 21 mpg.

It is also worth noting that I only fill the car with premium gas. That is reflected in the gas prices below and contributes to my above average cost per mile.

Number of fill ups
EPA's estimated mpg
Average fill up
Total spent on gas

I was curious to see if there is any correlation between the cost of gas and my driving habits. I remember thinking when gas approached $5/gallon in San Francisco in July 2008 that I would stop driving as much and bike more. In the chart below, the blue line is the average monthly gas price, and the orange points represent fill ups. The value is the approximate number of miles driven since the last fill up, using the EPA's mileage per gallon average for my car.

It does not appear that I drove distinctly less as the price of gas increased, but the fill ups were somewhat less frequent than in my first four years of owning the car, when I drove to work regularly.


The EPA estimates my car emits 370 grams of CO2 per mile, which means my car has emitted 63,029 pounds (or 29 metric tons) of CO2. According to the EPA's greenhouse gas equivalency calculator, that is equivalent to the carbon sequestered by 23 acres of U.S. forests in a year. Or, related to my profession, it is equivalent to 230,033 hours of computer usage — 26 years.

Total gas consumed
2,846 gallons
CO2 emissions
63,029 lbs
Continue reading in the surprise sequel: Part II »

# Caveats, Mistakes, and Mea Culpa

I am no statistician, nor a data scientist. I just wanted to see what I could come up with that might be interesting in this data. I am sure there are flaws in the analysis, and there are certainly some caveats you should know about:

  • All costs are “nominal” and have not been adjusted to current money
  • No cash transactions are captured in my records
  • Parking for other peoples’ cars is probably recorded in here
  • Same goes for gas


  1. In no way do I believe free parking is a basic civil right. That should be fairly well reflected in my willingness to pay for it. I do believe that our assumption that free parking will always be available has caused a crisis in our cities as well as our suburbs. Professor Donald Shoup, of UCLA, explains it much better than I. Feel free to read his research paper on the subject, or if you only have five minutes, watch him explain it to you directly.

# Sources

Retail gas prices
U.S. Energy Information Administration
Fuel efficiency data
U.S. Department of Energy
EPA Carbon equivalents
U.S. Environmental Protection Agency
Carbon equivalents
Science 2.0
Car ownership costs
Roof rack fuel penalty
Yuche Chen & Alan Meier