Driving: Fixed versus variable
Wanted to point readers to a discussion between Austin Contrarian and myself about fixed versus variable costs of driving, and how best to account the fixed costs. One thing many commute calculators get just absolutely and stupidly wrong is the idea that depreciation is a factor of miles driven (it's actually far more a factor of age - miles a distant second). For instance, this is a comparison I ran for one of the early comment's on AC's post: a 1998 Honda Civic LX, automatic, all other values default. All values as "private party" and "excellent condition".
(KBB said 86,000 would be "typical", but actually seems a bit low to me).
A 1998 Civic would be either 9 or 10 years old today, depending. The added depreciation due to driving normally versus the little-old-lady case is no more than $100 per year ($8.25 per month). The depreciation due to age swamps this figure by a factor of 10 or more. This stands to reason - would you really pay a ton of money for a 9-year-old Civic just because it wasn't driven very much? Of course not.
What does this mean? Ignore the commute calculators which include depreciation, insurance, and registration, unless you're one of the vanishingly rare few people who can completely get rid of a vehicle. Instead, use one of the calculators which only includes truly variable costs, like mine (originally written for bike commutes, but can be used to compare the cost for transit commutes just as easily - just zero out the cost of bike tubes and tires and put bus fare in "extra costs"). For instance, at gas prices of $3.00, and with $80 tires (about what our last set cost, each), you end up with these values for some of my old commutes (assuming I got to use our Prius instead of what I actually drove back then, which only got 38 mpg):
|Home to 183/Braker (Netbotz)||$1.31||$1.00 / $2.00 (regular / express)|
|Home to downtown (free parking)||$0.46||$1.00|
|Home to downtown ($8 parking)||$8.46||$1.00|
Now, if AC's parking cost was unbundled - charged per-day, his commute would actually come out cheaper on the bus by a fair margin, as indicated above. He indicated a monthly cost of $100, and I'm just guessing that $8 might be the price on the spot market, but that means that if he drives even about half the time, it'd be smarter to pay for the parking pass and then drive every day.
How can we fix this? If more of the costs of driving were borne directly by drivers, at the time they drove (or at least paid for gas), it wouldn't be so artificially cheap. For instance, when I drive downtown, I'm using roadways which were paid for out of property and sales taxes - not the gas tax. If we were to pay for all major roadways out of the gas tax, well, first, Round Rock would start to have to finally pay something approaching the cost of their infrastructure without free-riding on Austin, and second, at the extra buck a gallon I figure it would take, the math would shift a bit. It'd shift more if we could get auto insurance priced by the mile (although you keep hearing about it, it's never been an option for me or anybody I know personally). And, of course, if we paid for the costs of our Iraq adventure by gas taxes instead of through income taxes, the story would be even more different. But in the meantime, it rarely makes sense on purely economic grounds to ride the bus, even at our currently way-too-low fares so we're going to have to keep working on the other reasons. Like reliability. Light rail, dependable in time and at least competitive with the car, on which you could comfortably work or read, would be an easy winner. City buses - well, I salute AC and Tim for being able to work and/or read on the jerky city buses, but I was never able to, and I doubt most people would consider it acceptable even if saving a couple of bucks. Unfortunately, of course, our brand-new commuter rail line is going to inflict two of those jerky bus rides on every single rail passenger every single day. Oops.