To the casual observer, transportation may seem to be an egalitarian aspect of metropolitan life. The vehicles of the wealthy travel in traffic jams at the same speed as those of the poor. An overcrowded rapid transit system leaves all passengers uncomfortable regardless of social class. But access to the means of transportation and to the destinations they connect is distributed highly unequally in cities of the developed and developing world—an inequality that affects nearly all aspects of the lives of people with limited ability to reach their destinations. This presents a particular challenge for equity-based planning.