A methodology for calibrating microscopic simulation for modeling traffic flow under incidents

Incidents cause significant delays and their impacts on traffic flow need to be modeled to evaluate and mitigate them. The objective of this paper is to provide a methodology for modeling incidents in microscopic traffic simulation environment. Queue lengths and shockwave propagation speeds resulting from incidents obtained from analytical kinematic wave theory (Lighthill - Witham - Richard or LWR) were used to calibrate incident model in microscopic traffic simulation (VISSIM). A two lane freeway along the HRBT corridor was taken as a test bed. Fundamental diagram corresponding to the corridor was developed using Van-Aerde traffic mode and was used as an input to LWR. Queue length as a result of incidents blocking only one lane and both lanes were analyzed. Reduction in capacity, as suggested in HCM, was considered in the process of incident model calibration. The results suggest that a well calibrated incident model in VISSIM is capable of reproducing the queue lengths and shockwaves obtained from LWR and thus can be used for understanding the impact of incidents on freeways and testing alternative traffic management strategies, e.g., minimize delay or emissions.