Land-Use Conflict and Traffic Congestion on the N12: Evaluating Planning Responses at the Moroka Bypass, South Africa

Rapid urbanisation and an increasing demand for housing in land-constrained areas often intensify land-use conflicts and place significant strain on existing transport infrastructure. In South Africa, national road corridors are critical connectors between towns, cities, and provinces. The integration of well-designed on- and off-ramps is essential to sustain efficient mobility. However, stop-controlled intersections on these corridors, as opposed to grade-separated interchanges, cause significant disruptions to traffic flow, accessibility, and safety, uncovering weaknesses in integrated and sustainable planning. This study examines the R558 stop-controlled intersection along the N12 at the Moroka bypass and compares its performance with four on-and-off ramps serving Soweto and surrounding neighbourhoods along the same corridor. Using quantitative methods, it is possible to confirm or disprove a hypothesis, as the formulae can be tested repeatedly. Spatial data was also consequently used to visualise these trends. Findings indicate that the four ramped interchanges effectively support traffic flow, access, and movement along the N12, demonstrating resilience against increased development pressures. In contrast, the R558 stop-sign intersection performs poorly, characterised by congestion, increased travel times, and heightened safety risks. The study also reveals that inadequate integration of transport planning into rezoning and residential development decisions exacerbates these problems, undermining mobility and regional sustainability. It concludes that sustainable and resilient infrastructure planning, particularly the timely provision of grade-separated interchanges, is essential to mitigate traffic conflicts arising from new developments in land-constrained areas.