This chapter discusses the critical importance of urban design and its focus on public environments in cities, and some historical commentaries that help to show why the profession has been propelled into greater prominence in the field of sustainable transportation and healthy communities. Most importantly from a sustainable transportation perspective, urban design is a major player in whether urban fabrics are developed to encourage trips by foot, bicycle and public transit, as opposed to primarily facilitating the movement of cars. The chapter explores key aspects of the urban design discipline and highlights some distinctions between it and the urban planning profession with which it is closely allied. It provides the rise of urban design is reflected in a wider range of additional resources, tools and efforts worldwide. The chapter describes a counterpoint to the inclusive, permeable and attractive public environments are the gated community.