Alright, what if it's a mile or two? When I was a student I used to walk a few miles a day around town because I didn't want to pay for a transit pass. I was young, broke, healthy (and the walking helped me stay that way); I didn't particularly enjoy walking but liked walking more than I liked spending a dollar on a bus fair.

I don't think you can write off the decrease in foot traffic free public transit would cause.