Traffic Kinematic Waves at Road Hump Zone: Perceptions and Analysis

Aims: Traffic kinematic and shockwaves have often been used interchangeably in any literatures.The paper investigated traffic kinematic waves at road hump zone and their shockwave implications.
Study Design: Road hump impact study.
Place and Duration of Study: The study was carried out at locations along Jalan Universiti, Skudai, Johor Malaysia, between April 2012 and October 2012.
Methodology: Based on the hypothesis that road hump cannot be held solely accountable for traffic shockwave occurrences, with and without road hump impact study was carried out at four sites in Malaysia. Road section was divided into two sections A (without road hump) and B (with road hump). Traffic volume, speed, headway, gaps and vehicle types were collected with automatic traffic counters continuously for eight weeks. Empirical data were supplemented with design data supplied by ministry of works. Data were collated and compared.
Results: Results show that road humps are effective speed reduction mechanism. Although speed reductions were recorded, traffic shockwaves were not recorded and also there was no evidence to suggest that significant kinematic waves were caused at road humps. Differences between traffic shockwave and kinematic wave results affirmed that traffic shockwave will only occur at the capacity constrained section of flow/density curve.
Conclusion: The paper asserted that traffic kinematic wave and shockwave propagations are related but not the same and concluded that road humps cannot be held solely accountable for traffic shockwaves. Further, that traffic shockwave is more likely to be caused by the led driver’s erratic behaviour on approach to the barrier.