Intersection safety : a Tshwane case study

Abstract

The Safe System Approach (SSA) advocates for a forgiving and self-explaining roads and covers aspects such as safer vehicles, safer speeds, safer roads, post-crash care and safer people. The principles that SSA incorporates are zero tolerance for death and serious injuries, human error is inevitable, human vulnerability, shared responsibility, proactive interventions for safety, and redundancy of the transport system. This case study considers road safety aspects at a specific intersection in the City of Tshwane. The study made use of observations and traffic conflict modelling tools to assess intersection safety. Effective planning of intersections is essential in transportation and road safety engineering. Intersections are critical junctions in the road network where various traffic flows converge and where the potential for traffic conflicts is higher. The intersection design significantly influences safety, traffic movement, and the overall efficiency of the road system. It has been observed that when vehicles approach the full access intersection (T-junction) to make a right turn, drivers experience restricted visibility of oncoming traffic from the right due to parked vehicles along the roadside. This configuration forces drivers to advance cautiously into the oncoming traffic lanes to gain a clearer line of sight, leading to unsafe turning manoeuvres and traffic conflicts. Additionally, these vehicles are required to queue within the intersection between the traffic islands, while waiting for a safe gap from the oncoming traffic from the left to complete their turn and merge onto the lane after making the turn. This operational challenge raises concerns regarding the potential need for a traffic signal or a general intersection upgrade at the intersection, or similar intersections with comparable safety and flow issues. This paper concludes with recommendations to address safety concerns at this intersection type aligned with the Safe System Approach.