12 A Sociology of Traffic: Driving, Cycling, Walking Jim Conley in Phillip Vannini, ed., Technologies of Mobility in the Americas. Oxford & Bern: Peter Lang, 2012 pp. 219-236. In 1968, Norbert Schmidt-Relenberg (1968/1986, p. 121) wrote that “an analysis of traffic can enrich sociological theory.” Little became of his hope, but, in the interim, the “mobility turn” in the social sciences has transformed our understanding of all forms of movement, including automobility. This chapter develops a sociology of pedestrian, bicycle, and automobile traffic by considering driving, cycling, and walking as socially interactive mobilities. The complex coordination of movements between the multiple independent units that make up car, bike, and foot traffic are performed by and between the mobile units themselves, largely through looking at each other. In contrast to the “eye in the sky” view of traffic planners and engineers, for whom traffic movements are akin to flows of particles (Lynch, 1993), and to studies of the physical, emotional, and aesthetic experiences of individual drivers, cyclists, and pedestrians, the relational approach developed here shows how the material characteristics and speed of these pedestrian, bicycle, and automotive assemblages provide opportunities for and limitations on visual contact and social interaction between them. Starting from Simmel’s reflections on the “sociological eye,” I develop a typology of mobile looking. Turning then to Goffman, I extend his understanding of traffic as a social order by examining in detail how walking, driving, and cycling as forms of mobile interaction are affected by the material characteristics and speed of the mobile units. Simmel: The Sociological Eye In his influential essays, “The Stranger,” and “The Metropolis and Mental Life,” Georg Simmel (1903/1971a, 1908/1971b) examined how urbanization and modern mobilities affected social life in the nineteenth century. In this context, his remarks on the sociological function of the eye have often been cited in the mobilities literature, notably by John Urry (2004, p. 30; 2006, p. 21; 2007, p. 24). Their significance has not been fully explored, however. Simmel (1908/1969) stated: Of the special sense-organs, the eye has a uniquely sociological function. The union and interaction of individuals is based on mutual glances. . . . This mutual glance between persons, in distinction from the simple sight or observation of the other, signifies a wholly new and unique union between them. The limits of this relation are to be determined by the significant fact that the glance by which one seeks to perceive the other is itself expressive. By the glance which reveals the other, one discloses himself. . . . What occurs in this direct mutual glance represents the most perfect reciprocity in the entire field of human relationships. (p. 148) As a way of “knowing” others, sight predominated over hearing in the city, Simmel argued. He explained this in part by “the development of public means of transportation” which put people in “a situation where for periods of minutes or hours they could or must look at each