dead dinosaur, it's what's for dinner.

I’ve spent some time cleaning up my car spreadsheet tonight. I still have some issues with my methodology on calculating MPG, but I’m pretty comfortable with my $/gallon numbers.

And oh, what a story they tell:

The above graph depicts the rising cost of gas in the Washington, D.C. area (specifically in Alexandria, VA.). The data is entirely from logs kept in my car since April 2002.

• Before the Katrina spike of August/September 2005, most of the spikes were caused by travel to different areas. The overall trends stand out amidst the noise, though: each year, the summer rise is greater than the previous year’s fall. And so prices go up.

• Starting in August 2006, I began travelling to the Virginia Pennisula, where gas prices were cheaper than in D.C. (usually by about $0.20/gallon). This is why the recent data shows an interesting wave pattern as I would alternate fillups. The really low price last weekend was near Orange, VA, at $2.64/gallon for premium.

• Prices have begun to fall somewhat as autumn approaches, though prices remain above $3/gallon at the local station.

I find the data endlessly fascinating.

• To date, I have purchased 2,675 gallons of gas at a cost of $5,558.88. That’s an average of $2.08/gallon.

• If I had purchased it in bulk in 2002 (when I bought the car), I would have paid $3,766 for it. (That’s $1.41 a gallon).

• In 2005, I bought 543 gallons for $1,317.21, or $2.42/gallon.

• For 2006 year to date, I’ve bought 505.1 gallons for $1,450.76, at $2.87/gallon. I’ve also already driven 12,866 miles, or 65 more miles than in all of 2005.

I originally started keeping track of my mileage because I wanted to calculate total cost of ownership of my car. The historical data, though, is proving far more interesting.

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