Traffic Signal Preemption and Prioritization for High-Density Road Networks

Traffic signal priority and preemption modify the traffic signals, offering priority to specific vehicle types, such as buses, streetcars, or emergency vehicles. Specialized hardware and software systems are developed to facilitate the preemption and prioritization signal application (PPSA). Nevertheless, the international standards and the existing research works focus on providing a solid foundation for the application, rather than deploying them in high-density road networks, where the distances between two consecutive intersections are shorter than typical roads and are commonly seen in Southeast Asia cities. The shorter distances between intersections result in less time for the vehicle drivers to react when the PPSA does not grant their request, raising safety concerns. This work proposes a software framework for the PPSA, including a detailed analysis of the international standards related to PPSA, a timely response mechanism (to provide a longer reaction time after thoroughly analyzing the standards for exchanging messages), and a time estimation model (to evaluate if the system configurations have safety concerns). Experiments are conducted on our prototype system with actual hardware platforms. The experimental results show the proposed framework works well for high-density road networks. The time estimation model can be used to assess the traffic safety of PPSA systems under different system configurations. The proposed framework, standard protocol analysis, and time estimation model can be used by system designers to improve the safety and efficiency of PPSA systems, especially in areas with small street blocks.