Rational choices adding up to insane results

I really like Andy Clarkes' pithy description of one of our contemporary rituals:

"Just look at the madness we create for ourselves with the school trip: 20%-30% of morning rush-hour traffic in many metro areas consists of perfectly able-bodied kids being ferried to school by parents with better things to do with their time who won’t let their kids walk or ride their bikes to school because there are so many harried parents rushing their kids to school and the roads and sidewalks around the school aren’t safe. And frankly, many of the kids could use the exercise."

This evokes the old prisoners dilemma situation. Everyone would presumably be better off if children had a safe environment to get themselves to school, but each person is individually worse off if everyone else chooses to drive and their child is the only one stuck breathing the exhaust. Clarke is right in calling this "madness," but it's a particularly insidious form that feeds off of mostly rational individual choices. As frustrated as parents may be with this vicious cycle, especially those who hold to personal principles of environmental stewardship and healthy lifestyles, few will want their own children to be the ones breaking it. So they drive.

I try to remind myself how structural, not necessarily personal, the ethics of transportation and land use are.