In an effort to justify her cycling habit, Bike Girl put on her sexy nerd-glasses to do some commuter math. She wanted to find out if her commute actually saves her any money, or if it's simply an indulgence that allows her to feel smug with her bicycle resting against the wall of her cubicle.
Bike Girl bit on the end of a pencil eraser and scratched out some FORMULAS.
Miles driven divided by MPG = gallons used.
8.6/30 = .29
Gallons used multiplied by price per gallon = total price spent for miles driven.
.29 * $4.55 = $1.30
Since Bike Girl sometimes takes the Metro one way to avoid getting extremely sweaty before work, she subtracts the cost of the ticket from her gas savings.
$1.30 - $1.25 = $ .05
Bike Girl's daily commute saves her 5 cents on gas. If she commutes at least three days a week via bicycle for 50 weeks a year, her savings will add up to $7.50 a year.
Such a small number surprised Bike Girl. So she has decided to focus on other advantages to bike commuting. She has decided it is still worth it!