Transportation affects peoples’ day-to-day lives in myriad ways, including the ability to get where they need to go, the economic wellbeing of individuals and communities, physical and mental health, and the health of the local environment and planet. Transportation agencies are becoming increasingly interested in measuring accessibility, or the ease with which people can reach desired destinations. In part, the concept is attractive because it reflects the primary purpose of a transportation system—to connect people to the opportunities they value.