ABSTRACT
This chapter draws on the partial shift from police-controlled to machine-controlled mobility in interwar Stockholm. It begins by reflecting upon what has been termed the "traffic crisis" of the interwar period, considers the process of technology and knowledge transfer in the introduction of traffic control measures in Stockholm, and evaluates the piecemeal transition from hand-signalled to mechanised control of urban mobility. Drawing upon archive material, newspaper articles and published material related to the introduction and early development of traffic lights, the chapter aims to explore what lights "do" in a Latourian sense. It highlights design as a political and interest-driven domain, and the role of artefacts in producing mobility. The chapter outlines an actor-network-inspired approach to understanding traffic control. In de-scribing traffic lights, articles in Swedish press on the limits of police officers' hand signals are as revealing as those hailing optical signals as a measure of modernity.
