How to buy a car using data

Guest post by Dev Nambi
We like reliable steeds. Photo by Moryan Brenn.

My wife, Kate, and I were perfectly content to drive her car, a 1995 Honda Civic. It never gave us trouble…until it died last December. Then we needed a replacement.

After mourning the passing of our reliable steed, we decided we did not care about specific car brands or models. We cared about features. Our goal was to buy a car with features we care about, for the best price. Our first step: decide what functionality we wanted most.


We spoke for an hour, and made a list of desired features. This was the place for each of us to say what we thought was important; other people will have different results.

Must Have

Feature Reason
Better than 27 mpg city, 37 mpg highway We like the environment. That is what our old car did.
Highly reliable We like low maintenance costs
Good crash test ratings/data We like safety
Lasts at least 5 years The cheapest car is the one you already own
Anti-lock brakes & air bags We like safety
Enough space for a baby seat We’ll need that in a few years
Cruise control Makes road trips easier
Audio line-in jack, for iPods We like music
At least 10 sq ft space in the trunk Necessary for camping trips
Range of at least 500 miles per day Necessary for road trips

Nice to Have

Feature Reason
CD player, radio good speakers We like music
Sunroof We live in Seattle
Power windows, door locks We’re lazy
Leather seats Easier to clean child-induced messes
Lasts 10+ years We’re really cheap

Now that we knew our goals, it was time to learn the game


Both of us have heard horror stories about the car buying experience. Neither of us had done this before. So it was time to learn. We used our favorite resource: The Internet.

A few web searches found dozens of articles discussing the best ways to buy a car. We read through the top 30 and took notes. From that we made a list of best practices when buying a car.

We also found there is a balance between features, price, and reliability:

Lessons Learned

  • Best practices for car shopping
  • Things to avoid when car shopping
  • Get a used car if you want a deal


Armed with our list of features, we started looking at different car models made since 2004. I found and to be

Wow, data is really useful!
particularly helpful here. A couple hours’ web browsing found 27 models that fit our criteria. Now the fun part: data!

Our top criteria were reliability and fuel efficiency. So, we documented each car’s gas mileage, and created an “Internet score” that counted how often each model was included in articles about “the most reliable used cars” or “the top 10 quality cars by BigCarWebsite.” A little Excel conditional formatting, and voila! We ended up with this:

We removed cars with bad gas mileage (less than 29 mpg combined), and with an Internet score of less than 3 (not reliable enough). That left 7 cars.

Next, we compared each car’s specs with our list of must-have features. This led to 4 more disqualifications:

We were left with 3 cars: the Honda Fit, the Honda Civic, and the Toyota Prius. They became our short list. Now it was time for test drives.


Test driving a car isn’t about data. Driving a car is subjective. If we think about why a car feels a certain way, a test drive can provide a wealth of information. One day, three test drives and two auto dealerships later, Kate & I came away with some pros and cons for each car, but we liked all three of them.

Additional web research showed that none of our cons was justified. The only lesson was realizing that a Prius is very mechanically complicated. So we should only look at Priuses (Prii?) with warranties.

In our next post, we will analyze specific cars for sale, looking for the best deals, still using hard, cold, data. Come back tomorrow for the exciting conclusion!

Comments on How to buy a car using data

  1. What a useful post! My husband and I are looking at getting a used vehicle because we now have two large dogs and a baby on the way with no way for all of us to get around once the baby comes.
    Maybe it’s my perfectionism at play but I LOVE using data like this to help me decide on a big purchase.

  2. Awesome, I cannot like this enough! I’m a sucker for seeing data presented to me so I can evaluate everything.

    On a complete tangent: I wish horses were still an acceptable form of transportation beyond leisure. (…horses and scooters)

  3. Hah! We went through exactly this process 3 months ago, and had pretty much the same list of criteria. We also wanted a car that fit our budget (this eliminated the Prius, which had been on our list) and a car that could fit music gear (so, a hatchback: lugging keyboards and amps into a non-hatchback small car at 3am after a bar gig is murder…)

    We wound up with a Honda Fit, and I’m really quite satisfied with that particular decision. Among other things, I fill the gas tank every 2 weeks, and I work 25km from home – given gas prices, that definitely a plus right now! 🙂

    • We’ve had our Fit for nearly four years (we had to buy it new because the used 2007 models cost almost as much as a brand new 2008 model at the time), and we completely still love it to pieces. It fits all my husband’s band’s gear except the drums; we’ve fit bookshelves from Ikea, a water heater once, our bikes, furniture from Craigslist, etc. It’s awesome for camping and roadtrips and drive-in movies, and we’ve squeaked into teeny tiny parking spaces with it. I did a ton of research before we bought our car because we were going from a minivan + sedan down to one vehicle, and it had to be perfect. This was the best choice and still is multiple years later.

      • I’ve got a 2008 Fit as well and I tell everyone who’s looking for a car to consider it because I’m very much in love with my car. There’s just so much room in what looks to be a small car. Having the seats fold all the way down is a major plus in my book because it means I can fit pretty much anything back there and my dogs like it for longer trips.

  4. This is fantastic! When we have children in a year or two, my husband and I will probably need to buy a second car. I’m loving the 2000 Volvo station wagon we got in August, and I’d like to get another used car when the time comes, but had no idea how to go about it. I’m bookmarking this page for sure!

  5. I did this on the very first car that I bought! The hardest part for me was the initial stage of getting all types of cars, it was kinda sad to see some of them added then taken off just as quickly. But now I know for sure that my car is a CHAMPION!

  6. I have a Toyota Corolla (2009) with cruise control. Not sure where you’re getting your data from. (It does look like 2009 was the first year the Corolla routinely came with cruise control.)

  7. i’ve gotta defend the Sonata, here. the 2011+ redesign brought with it increased fuel economy (i regularly see 28 in the city if i don’t drive like a jackass) and i’ve gone nearly 500 miles on one (admittedly large) tank before.

    of course, this just on the newest model, and YMMV.

    said redesign also brought a hybrid option and a lifetime warranty on the battery…which is something i don’t recall any of the other manufacturers offering.

  8. Nice post!

    One thing I would add in though is to take the car to a local mechanic (other than the dealership’s mechanics) to have them look over the car. Most mechanics will do a pre-purchase inspection to alert you of any items that may not be up to par with the car.

    Also, certain car types and brands will cost more to repair if something does break down later. Like for example, the batteries on many of the electric cars. After 5 years, the batteries need replacing. Unfortunately, the cost of these batteries are outrageously high ($500 and up per battery for the mechanics cost, not including a mark-up after that for a profit margin) and not covered by insurance. Or for another example, the parts are expensive and dealer only… meaning there are not any cheaper after market parts available (ex: Mercedes).

    Also, as a tiny gripe… any car can last longer than 5 years with proper care and maintenance. Keep up with the oil changes and always bring it in for it’s tune-ups / inspections and it will easily last past 5 years. My car is coming up on 190,000 while my guy’s cobra is around 170,000.

    Sorry for the long post, my guy is a mechanic and I’m a bit of a car (Ford Mustang) nerd. Also, we work on project race cars on weekends as a hobby. =)

    • While I agree with you on all the maintenance bits, most European cars do have original equip manufacturer parts you can get aftermarket. The only one that doesn’t is smart cars. There are loads of independent mechanics for everything from classic cars to hyper exotics 🙂 (I work at one!)

  9. This post was already amazing, but then I saw the conditional formatting in Excel with color-coding and just about fell out of my chair from the awesomeness. Thank you.

  10. I totally LUV this!!! I love data and spreadsheets. I should definitely do this. I have a 2004 Suzuki that I want to have go bye-bye. It’s been decent, but it doesn’t have the gas mileage I want, or the ground clearance. When you get stuck on a big snowdrift in your driveway in winter and can’t get out, that’s NG. My must haves: AWD or 4WD because I live in Alaska and I refuse to drive here without it. At least 22-23 Hwy MPG since I now live 50 miles from work and that’s most of the driving now. Room for at least 2 kids in the back plus booster seats. (Preferably more since I want more kids). Bluetooth! 🙂 There’s a few more, those are my biggies. I think I need to make a spreadsheet!

  11. I just bought a new car literally 4 days ago. My 2001 Hyundai Accent was nearing the end of its life and I didn’t want to keep fixing it. I am already a very indecisive person, so putting the big decision of spending a huge amount of money made it very difficult. It eventually just came down to price. My mom helped me negotiate the price and I am a happy owner of a 2012 Hyundai Elantra and I love it.

    I just want to stress the importance of negotiating with the dealership. Some places are very stingy and won’t do anything you are. I encourage you to find someone who is will to work to get you the price you want. We got almost $3000 off compared to another dealership we were dealing with.

      • I know! It’s true of the Insight too. I was all set to get a Honda hybrid because I lurved my old civic Eleanor with a passion, and hey, hybrid, bonus. But they actually keep the hybrid battery in the back seats. Totally bizarre.

  12. For what it is worth, we have two child seats in our 4 door hatchback Toyota Yaris, so I wouldn’t say that the Yaris doesn’t fit a child seat easily. We absolutely love our car. There isn’t a ton of cargo space, but the short length of the car makes parking on city streets much easier!

  13. Thanks so much for posting this! Your requirements were almost exactly the same as ours, so it saved us a ton of research. We bought a new Civic on saturday!!!!

  14. Know thyself! so so true. We always come across car buying prospects that want sports cars or big trucks and their lifestyle just doesn’t require what they are looking for. Whether looking for a new car( which i don’t recommend) or a pre owned car make sure you understand your needs and what will actually benefit you

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