Risk management assessment of mobile crowds: The case of the Black Nazarene procession in Manila, Philippines

The Philippines is a highly Christianized country where religious events, such as the Black Nazarene procession, are celebrated on a massive scale. The annual procession, characterized by devotees pushing the carriage of the Black Nazarene, in the city of Manila attracts thousands of devotees. The 2019 procession took 21.35 h to traverse a 6.94-km route at an average speed of 0.33 km per hour. The extreme size and density of attending crowds make injuries and fatalities a common occurrence. Despite the usual risks that similar events entail, limited studies have been conducted to characterize and evaluate big crowds. This study developed methods and policies that aim to improve risk management planning for the event. Using video graphics, a static grid analysis was performed to systematically evaluate and capture actual participants' density and speed. The aggressiveness, density, and group formation of devotees at varying road widths were found to significantly influence the procession's movement throughout its duration; at least 56 pedestrians are needed to push the carriage from behind for smoother forward movement. Finally, proper allocation of human resources by local government departments involved in event management was recommended to potentially minimize the incidence of related injuries and deaths. •The annual Black Nazarene procession in the City of Manila attracts massive crowds.•Increased devotees' aggression is observed along narrow roads inducing frequent and longer parade stoppage.•Average procession speed along whole route is approximately linear despite varying road features and crowd behavior.•Risk hotspots due to devotees' aggression were identified for additional safety personnel allocation.•Optimized push formation causes smoother and safer parade flow