A number of cities in Africa experience very rapid spatial growth without the benefit of a systematic process of planning and implementation of planning decisions. This process has challenged the road and transport system, created high levels of congestion, and hampered mobility and accessibility to both central and new peripheral areas. This paper reports on studies carried out in Accra and Dar es Salaam to address and link 1) mobility practices of residents, 2) local strategies for ‘post-settlement’ network extension, and 3) the city-wide performance of the transport system. The studies draw upon qualitative interviews with residents as well as road network data and travel speed data collected with GPS to offer a combination of local testimony with GIS-based modelling of overall accessibility. It is argued that the use of digital network analysis enables planners to obtain a better knowledge of the spatial patterns of urban accessibility, while the analysis of mobility practices of residents enables a better understanding of the constraints people experience related to their livelihood strategies. Finally, the paper addresses how local residents engage in providing and improving neighbourhood service levels, including road infrastructure, in the period following the development of a residential area. It is argued that this ‘self-help, post-settlement’ development of infrastructure can be necessary due to the inability of the planning system and service providers to provide services in advance. However, such solutions are often impeded by costly and cumbersome land-acquisition processes, and because of the reactive and often piecemeal approach to infrastructure extensions, the development will often be more costly. Moreover, the lack of compliance to a city-wide development plan and the fragmentation of the infrastructure development means that there are major inequalities between urban areas.