Improved Dynamic Threshold Timer for Emergency Vehicle Preemption Exit Strategy

This paper examines the Dynamic Threshold Timer (DTT) as an exit strategy for Emergency Vehicle Preemption (EVP), a critical service that prioritizes emergency vehicles’ passage through traffic by pre-empting traffic signals. However, the use of EVP can lead to traffic congestion and delays for other vehicles. To address this issue, an Exit Strategy can be used to optimize traffic signal timing and improve traffic flow, thereby mitigating the negative impacts of EVP on other vehicles. The study focuses on a case study of one such strategy: Dynamic Threshold Timer, which was enhanced and evaluated for its effectiveness in reducing waiting time. The results indicate that the improvisation of DTT into the Dynamic Exit Phase can significantly reduce the average waiting time by 18% across all traffic flows saturation level. In contrast, the Fixed Phase does not reduce congestion but rather increases it by 10%, compared to a traffic light system without the Exit Strategy. Furthermore, the study reveals that applying DTT with an exit to the South Phase yields the most effective results, reducing waiting time by 20%. The findings from this research underscore the potential of utilizing DTT with exit strategies for the Dynamic Phase to improve traffic flow and mitigate delays. The implications of this study are significant for managing smart city transportation systems and enhancing emergency service provision.