Ridesharing has become a hot topic in research and in the media, largely because of the recent rise of platforms like Lyft and Uber. Yet shared taxis and paratransit services have played central roles in many African countries' transport systems for years. We conducted an ethnographic study of shared taxis in Windhoek, Namibia, to understand how ridesharing is achieved in this setting, including the drivers' orientations, concerns and practices, and their consequences for their passengers. Our findings lead us to suggest designing a different sort of ridesharing system to support the drivers' agency and tempo, which enables drivers to locate customers in a more ad hoc way than established digital ridesharing platforms. This contributes to a growing body of research on designing for ridesharing.