Long story short, I drive a Smart Car. So does the G/F.
37mpg tank average in winter. 41mpg tank average in summer.
My commute is 15 miles, and I drive like I stole it.
The G/F commutes 60 miles one way, and could not afford to work where she does if it wasn't for that car.
Besides the MPG, you need to look at $/mile. The Smart car is cheap per mile, around $0.30 without doing the math again. (At $4 gas). Tires are cheap, maintenance is cheap, repairs are cheap (if I would end up in a ditch during winter). Insurance is only $300 for full coverage a year.
I also have a 350Z I drive in the summer. I almost puked the first time I filled the tank this spring. Bike is cheaper, but not as good as the Smart Car.
Found my previous post on this matter....
With depreciation, gas, maintenance, insurance, etc.....
Smart Car Costs: $0.18 / mile (20,000 miles per year)
Speed Triple Costs: $0.47 / mile (5000 miles per year)
350Z Costs: $0.68 / mile (10,000 miles per year)
If I drive them all 20,000 miles (impractical), it would cost...
Speed Triple: $0.26 / mile
350Z: $0.45 / mile