Calibrating Volume Delay Functions for Urban Roads in Delhi, India

This chapter explores the calibration of Volume Delay Functions (VDFs) for urban roads in Delhi, focusing on improving traffic management and infrastructure planning. The study compares the performance of different VDF models, including the Bureau of Public Roads (BPR), Akcelik, and conical models, using real-time crowd-sourced data and videography data collected simultaneously. Key findings indicate that the calibrated BPR model consistently outperforms other models, particularly at higher volume-to-capacity ratios, highlighting the importance of local calibration for accurate travel time predictions. The research also validates the calibrated VDFs at a separate location, demonstrating the robustness and generalizability of the findings. Additionally, the study discusses the practical applications of using average values for VDF parameters in broader simulation models, ensuring adaptability and reasonable accuracy across varied traffic conditions. The chapter concludes by addressing the limitations of the study and suggesting future research directions, such as expanding to different road types and incorporating intersection delays and side friction in traffic models. Overall, the research underscores the critical role of local calibration and the potential of crowd-sourced data in enhancing urban traffic management and planning.