[testis321]

In my country (EU, so gas is a bit more expensive) the government calculates* transport costs at 0.37eur/km. So $0.45/mi would be in the right ballpark.

You have to account everything, not just fuel, from car depreciation, servicing (oil changes,...), normal wear (brakes, tires,...), occasional replacements (batteries, wipers, ...), etc. If you drive 20.000kms per year, and a yearly service (oil, filters,...) costs 200eur, just that adds aditional 0.01eur/km. Two sets of tires (winter/summer) are ~2300eur + 8 changes (8~40eur) adds an additional (almost) ~1k eur in four years, 1 more cent. Insurance, registration.. 3, 4 cents. etc.

*that's the untaxed amount you get reimbursed for if you use your own car for a business trip.

[AnthonyMouse]

There are two different calculations here. One is, what's the total cost of vehicle ownership amortized per mile? That's what the government and most popular types of accounting use.

The other is, given I'm going to own a car already, what's the difference between a shorter commute and a longer one? That's going to be a lower number per mile. A big chunk of the vehicle's depreciation is a result of years rather than miles, insurance doesn't generally track how many miles you drive and charge extra if you drive more, the registration and tax isn't any different etc.

The second one is how a lot of people end up all the way out in the suburbs. They can't afford to live in the part of the city that makes it viable to not have a car at all, but once you have a car as a sunk cost, another ten or twenty (or thirty or ...) miles in exchange for saving hundreds of thousands of dollars on housing starts to look like a good deal.

Though the huge factor people commonly forget is their own time. If your time is worth $25/hour then a half hour each way on your commute is $6500/year. And that's assuming you're only further away from work and not also further away from whatever you do on weekends.

[daurnimator]

> A big chunk of the vehicle's depreciation is a result of years rather than miles

Ehhhh, I'd say that it's not that skewed towards age of the vechile beyond common correlations:

  - usually more years = more miles
  - cars < 5 years are usually in warranty and fetch a premium

> insurance doesn't generally track how many miles you drive and charge extra if you drive more

Mine does: in 5000km increments. (Australia)

[AnthonyMouse]

> Ehhhh, I'd say that it's not that skewed towards age of the vechile beyond common correlations

But the warranty period is a huge amount of value, and there are others, e.g. newer cars are safer and have whatever other improvements so older cars aren't worth as much regardless of milage. Then many repairs are age related rather than mileage related, e.g. a car exposed to the elements will rust or experience day/night thermal stress even if you don't drive it.

> Mine does: in 5000km increments. (Australia)

Let me rephrase this. The insurance cost does not scale linearly with miles driven.

[benj111]

"Mine does: in 5000km increments. (Australia)"

Insurance has interesting edge cases, like 3rd party can be more expensive than comprehensive, as risky drivers go for the former.

I've had insurance before, where putting in a higher mileage lowers the premium. I assume there's a lower bound where you start getting into Sunday driver territory where risks start increasing?

[cardiffspaceman]

My insurance company has asked me to confirm my miles per year on occasion, especially the commuting part.

[sokoloff]

Most of the charges you list are mostly fixed (with time) rather than variable (with distance driven). Yearly service and yearly tire swapping: doesn't change by miles. Batteries and wipers: mostly fixed. Depreciation: probably 80% fixed. Insurance: mostly fixed. Registration: totally fixed.

On a marginal basis ("what does it cost me to drive one extra mile?"), I think my cost is about 7-9 US cents on my electric and about 12-15 US cents on my wife's CR-V. On an overall basis ("what does it cost me in total for the cars divided by how many miles I drove?"), the figures are more like $1/mile for the electric (still have a car payment, full insurance, and only drive 4500 miles/year) and $0.30-$0.40/mile for the Honda (paid off, so just carrying insurance, registration, taxes, and some timed maintenance items)

If we moved farther away, our fixed costs stay about the same, and it's only the variable costs that go up.

[bluGill]

I did account for everything above. I keep track of everything.

Note that I do my own maintenance on Saturdays, so I don't put a monetary value on my time. However before you say I should account for my time, do you account for your time taking the car to the shop - I started doing that a few years ago and stopped because I realized that for most things I could get it done faster myself than take it in. (taking it in accounting for all time getting the car to the shop, arranging rides (sometimes a loaner car, sometimes my wife's time), and paperwork. When doing the work myself I can stop at the auto parts store next to the grocery store and so much less time needs to be accounted for there.