Accessibility, congestion and travel delays in Dar es Salaam – A time–distance perspective

•OpenStreetMap data is applied for analysis of transport in Dar es Salaam.•City-wide maps of time-distance zones indicate long commutes to city center.•Locations of high congestion levels and travel delays are identified.•Rapid spatial expansion creates peri-urban areas with low accessibility.

This paper addresses the current state of the transport infrastructure in the city of Dar es Salaam providing both a methodological, a planning and a spatial accessibility perspective. Initially, a short background section describes the growth and spatial transformation of the city area based on spatially disaggregated data from the most recent inter-census period from 2002 to 2012. This period is characterized by extensive growth in terms of area, population and car use, while the road network largely maintains status quo except for ad-hoc development in new urban areas. The paper moves on to present a review of research into travel speed levels and congestion in Dar es Salaam. A set of city-wide maps of accessibility and delay levels are constructed based on available speed data and road network data obtained from the OpenStreetMap project and the findings are discussed with respect to the need for more efficient transport planning and implementation of plans.