A discrete event simulation for modelling Aljamarat Bridge rituals and evacuation scenarios

Hajj is the largest mass gathering event globally that occurs annually. It is a pilgrimage that lasts for about a week. The pilgrims perform rituals at different sites (The Grand Mosque, Mina, Arafat and Muzdalifah) in the city of Makkah, Saudi Arabia. Safety of the pilgrims is number 1 priority for the Saudi authorities and several new projects have recently been completed at the Hajj sites with a goal to improve proceedings. One of these projects was the redesign and construction of the Aljamarat Bridge at Mina City. This project was commissioned to mitigate severe crowd incidents at the bridge in previous years. The new bridge has greatly improved safety of pilgrims. However, unexpected hazards and accidents such as fire or gas leaks can occur, necessitating the evacuation of pilgrims from the bridge. This paper presents a model and simulation study of pilgrim evacuation from Aljamarat bridge using a Discrete Event Simulation (DES) tool called “ExtendSim”. The tool was validated by modelling and simulation of three million pilgrims based on a strict scheduling system that distributes them on each level. Based on our methods of allocating specific evacuation routes at each level on the bridge, the evacuation modelling shows promising results when using six towers, resulting in a smooth process without any crowd buildup.