The simulation of emergency dynamic scenarios through HARIA-2, a tool for the planning and analysis of technological emergencies

The paper begins by introducing HARIA-2, a methodology setup for external emergency planning and analysis, which takes into account the physical phenomena and the sociological aspects of technological emergencies. The paper then focuses on the module Dynamic Scenarios, which addresses emergency planning issues. The model includes road traffic and control of ingress and exit models, with the aim of minimizing population exposure. It integrates in simplified mode the data bases needed for simulating accident scenarios, including population behaviour and evacuation plan. The evacuation of people at risk and the intervention on the accident scene of the rescue teams are the most intriguing countermeasure to be undertaken during an emergency. Given the road network, described in terms of arcs and nodes, data on the maximum allowed speed on one-way roads, etc., the traffic model calculates for each arc the time evolution of density and flux of vehicles. This model uses the continuous fluid-dynamic analogy with the Greenshield correlation between speed and density of vehicles. To outline the main functions of the Dynamic Scenarios module, an example of application to an Italian industrial site is briefly described.