Articulated density : a study of its potential effects on the financial sustainability of South African BRT corridors

Abstract

The financial sustainability and continued roll-out of South African Bus Rapid Transit (BRT) networks has been questioned. The unique spatial structure of South African cities, in which the majority of residents live toward the urban periphery, has created an unsupportive land use environment and large catchment areas for the BRT trunk service routes. This paper investigates the potential for ?articulated density? to overcome this barrier to financial sustainability. This relatively new land use indicator refers to how strategically population density is distributed over a city, in relation to trunk service proximity. The paper utilises a simplified public transport corridor operating cost model to test the effects of varying degrees of population density and articulated density on the financial sustainability of a hypothetical BRT service. When tested in typical South African conditions, population density is found to have a weak relationship with the viability of the BRT service, due to the heavy reliance on low-efficiency feeder services. Furthermore, the large catchment area of the trunk route results in the BRT?s operational limit for passenger volume being encountered at gross population densities as low as 50 persons/ha. Density articulation is found to have a much stronger influence, as it diminishes the reliance on the feeder routes. However, if the catchment area of the BRT trunk corridor is reduced, the proportion that does not require feeder services increases along with the influence of population density. It is argued, therefore, that South African city authorities need to either prioritise density articulation in current BRT corridors or reduce their length and catchment area in order to attain more sustainable services.