As a public space, the environment of public transportation services is maintained by an ordered set of rules and conditions. Such rules and conditions are prescribed by law as they are in generally-accepted norms of social behaviour within public space. Through the examination of the Conditions of Carriage that govern bus transportation in Cape Town, South Africa, using Golden Arrow Bus Services, this paper seeks to highlight the myriad ways that urban public space on the move is mediated, negotiated and controlled through rules of conduct that differentiate mobile public space from its counterpart in the environment outside the bus. Understood as a mundane part of the social life of the city and its inhabitants, mobility in the form of public transportation is constituted by micro-communities whose publics are in a constant state of flux and negotiation. Using analysis of the Conditions of Carriage and an ethnographic case study of bus passengering, this paper demonstrates how the Conditions mediate the situated and lived assemblage of actors in mobile public space that is a liminal zone between inclusion and exclusion.