The Dupont-Rosslyn Circulator, one of my favorite public transit options in D.C. Photo by m01229, used under Creative Commons licensing. The Dupont-Rosslyn Circulator, one of my favorite public transit options in D.C. Photo by m01229, used under Creative Commons licensing.

I've lived in D.C. for seven and a half years now, which means I have a lot of feelings about public transportation in the city. This was still true back in December 2011, when I first read Jarrett Walker's Human Transit, and I remember nodding along enthusiastically as he made points like "Frequency is freedom." In the chapter excerpted below, he walks the reader through the seven demands placed on transit, which resonate with anyone who has navigated a public transportation system.