1. ¹Texas Center for Geographic Information Science, Department of Geography, Texas State University, San Marcos, TX, USA
2. ²Central South University, Changsha, Hunan, China

Correspondence: X Chen, Texas Center for Geographic Information Science (TxGISci), Department of Geography, Texas State University, San Marcos, TX 78666, USA. E-mail: xc1001@txstate.edu

Received May 2005; Accepted July 2006; Published online 18 October 2006.

Abstract

This study investigates the effectiveness of simultaneous and staged evacuation strategies using agent-based simulation. In the simultaneous strategy, all residents are informed to evacuate simultaneously, whereas in the staged evacuation strategy, residents in different zones are organized to evacuate in an order based on different sequences of the zones within the affected area. This study uses an agent-based technique to model traffic flows at the level of individual vehicles and investigates the collective behaviours of evacuating vehicles. We conducted simulations using a microscopic simulation system called Paramics on three types of road network structures under different population densities. The three types of road network structures include a grid road structure, a ring road structure, and a real road structure from the City of San Marcos, Texas. Default rules in Paramics were used for trip generation, destination choice, and route choice. Simulation results indicate that (1) there is no evacuation strategy that can be considered as the best strategy across different road network structures, and the performance of the strategies depends on both road network structure and population density; (2) if the population density in the affected area is high and the underlying road network structure is a grid structure, then a staged evacuation strategy that alternates non-adjacent zones in the affected area is effective in reducing the overall evacuation time.