Little sociological attention has been paid to children’s mobility in urban traffic and transportation systems, running counter to the increased overall interest in mobility and, especially, “metaphors of mobility” (John Urry, Sociology Beyond Societies, 2000). Presently, the dominating view on traffic behaviour is strongly shaped by the rationalist discourses of traffic safety and management research, leaving an open space for micro-sociological accounts of both children in traffic and traffic interaction in general. The paper at hand presents preliminary findings and related theoretical and methodological thoughts from a PhD research project on traffic interactions involving lower level schoolchildren in the Helsinki region. The project stresses the relevance of studying the ongoing negotiations and interactions whereby the daily flows of humans, technologies and various “hybrids”, such as car-drivers and cyclists, are combined into distinct traffic spaces. Examining the everyday interactions of schoolchildren as a part of pedestrian, bus, metro, cycle and car traffic, the project illuminates how the parameters of inclusion and exclusion, mobility and immobility as well as surveillance and autonomy locally shape children’s mobility and their competencies to interact with fellow road-users, passengers and traffic technologies. By delineating the agencies the everyday ordering of traffic ascribes to children, the project touches upon the tensions and ambiguities that children’s movement in public space entail for the dominant public order, manifested in various efforts to anticipate and regulate children’s traffic behaviour through, for instance, urban planning and parental surveillance.