Transportation, like most human behaviors, is shaped by a mixture of utility, convenience, visibility, and familiarity. As energy-conserving, satisficing humans, we reach for what is easy, what we can see, what we know. Nearly one-third of car trips in America, for example, take us less than one mile. Why not walk or ride a bike? Because our impulse to drive is a virtual muscle memory. Habits, notes Charles Duhigg, “shape our lives far more than we realize — they are so strong, in fact, that they cause our brains to cling to them at the exclusion of all else, including common sense.”
