Breaking down my gasoline consumption

With gas prices at their current levels people are hurting at the pump and even my 2.5 mile commute adds up. I usually go home for lunch so I’m driving 10 miles a day. Compared to the 50 miles I was doing one year ago I should be grateful my gas bill is as low as it is. The savings I’ve seen with a shorter commute aren’t quite as large as you’d think. The increased price of gas and lower mileage from city driving has doubled my cost per mile.

Gas prices have gone up considerably; here’s my data I’m collected over the past 2.5 years:
Price of Gas

Higher prices mean it costs more to drive a mile, no question there. Here’s my mileage over that same time period for my 2005 Toyota Tacoma 4 cylinder automatic:
MPG

When I started at the County last August two things happened: a tank of gas started lasting longer and my mileage plummeted. The short trip to and from work means my engine is operating at a less efficient temperature for a larger proportion of my commute. Coupled with stopping and idling at traffic lights I saw a 7-8 mpg decrease, that’s a very significant ~30% drop in mileage. My historic cost per mile looks like this:
Cost per mile

The double whammy of increased prices and lower mileage hurts. With my current cost per mile it costs me $2.20 to drive to work everyday. Doesn’t seem like much, but that adds up to about $550 per year. That’s just to get to work, that doesn’t include driving anywhere fun.

I’m going to go through a series of post analyzing my energy costs and figuring out ways to reduce them. What’s your daily commute cost you? Simple formula to calculate it:

Commute cost = (price of gas / MPG) * miles