Certainly that cost will be greater in the early life of the car. However, the fact that you devalue your car by driving it is certainly a cost of driving.

BTW, don’t agree that fixed costs like insurance are measured by mile. I think that is the cost of being ABLE to drive [or more specifically, being able to own the car], not actually a cost of driving. If you buy a vehicle and drive zero miles, you still have to pay for the insurance as long as you MIGHT drive the car.

Excellent post! Reminds me of Amy Dacyzyn.

Looking back over a year, or a month, you can see what the actual cost distribution per mile was, but it doesn’t affect a decision about making a quick run to the grocery store.

In light of these small extra trips is why I made the comment about insurance costs not really being a factor. I’m not concerned with the extremes of not driving at all or anything.

Conceptually, yes, if we stopped driving we would still be paying insurance. That is fixed (then again, if we are stopping driving completely, then why not just cancel the insurance?).

However, in application we are not going to stop driving any time soon. So within this relevant range of driving (say, any significant amount of driving above 0 miles), I think insurance can be broken down to a mileage estimate. I think this is especially true because we are driving a pretty consistent amount year to year.

It would be different if our mileage changed greatly from year to year. One year 5,000 miles and the next 15,000 is going to greatly change how much that insurance is costing per mile.

In the end, I was just trying to get a unit of measure for each mile we drive. Breaking it down to fixed, semi-variable, and variable costs (thank you accounting class) seemed a bit over the top.