Evaluating operational and congestion improvements associated with the dualling of single carriageway arterials

Abstract

Changes in land use zoning and major developments can generate significant traffic along major arterials, resulting in congestion and worsening operational conditions if no intervention is undertaken. Road authorities mitigate this through the upgrade of roads such as dualling single carriageway arterials. The purpose of this study is to evaluate the impact of dualling a single carriageway arterial. Congestion relief and changes in operational conditions are evaluated using Floating Car Data (FCD). The upgrade of the R310 from a two-way, two-lane road to a dual carriageway road with two lanes per direction between the N2 interchange and Annandale Road in Stellenbosch is used as a case study to evaluate travel time changes and average speed along the route. The use of FCD provides a greater understanding of the differential in travel times and average speeds of the two scenarios (before and after road upgrading). The analysis demonstrates improved travel times in peak periods. The impact of the implementation of an access management strategy and signalisation illustrates a significant impact on average speed at localised positions. This study has proven that the change in traffic characteristics when dualling a single carriageway can be better understood using FCD and can assist road authorities in decision making.