I am going to do math on my blog today. This will likely never happen again, so feel special.
Everybody knows gas is expensive, and that driving in general is often not the cheapest means of transport. There is a great blog post here, though, that tells you how to figure out just how expensive driving is for you. It's an exercise worth going through, so I'm going to do it here.
As the linked post mentions, I am only going to count gas, maintenance, tires, and depreciation in my calculation of per-mile costs, considering insurance, taxes, license and registration, and finance charges as costs of owning a vehicle, whether I drive it or not. I'm doing it this way on the assumption that having a car is necessary, but a lot of trips I make in it aren't.
My beginning numbers:
Our car is a 2006 Honda Element. It gets about 20 mpg in the city, where most of our driving takes place. We put about 7,000 miles a year on it. Current Blue Book Value is $17,225.
Step 1: Calculate depreciation.
$17,225 (current value) - $16,530 (estimated value with 7,000 more miles) / 7,000 (annula mileage = $.10/mile depreciation
Step 2: Calculate gas cost.
Gas here is currently an average of $3.79/gallon. We get about 20 mpg. That means gas costs for us are about $0.19/mile.
Step 3: Calculate maintenance and tires.
Here I am using AAA estimates of 4.67 cents per mile for maintenance and and .85 cents per mile for tires.
Step 4: Add it up.
$0.10/mile depreciation + $0.19/mile gas + $0.05 mile/maintenance + $0.01/mile tires = $0.35/mile total cost of driving.
So what does that mean? How much does it cost me to make non-necessary trips? Here are some examples:
Commute: Our daily commute is 7.2 miles each way, or 14.4 miles round trip (not including parking garage time). That's $5.04 a day commuting cost, or $25.20/week.
Target: If I go to the nearby Target from my house, it's 1.8 miles each way, 3.24 round trip. That's a $1.13 trip.
Goodwill: If I go the the bins from my house, it's 6.5 miles each way, or 13 miles total. $4.55 each trip. If I go to the other location from work, it's 4.7 miles each way (again not including parking garage), 9.4 total, for a $3.29 trip.
Well. That was an eye-opener.