We present a method for systematically identifying neighbourhoods that may face transportation difficulties during an evacuation. A classification of this nature offers a unique approach to assessing community vulnerability in regions subject to fast-moving hazards of uncertain spatial impact (e.g., urban firestorms and toxic spills on highways). The approach is founded on an integer programming (IP) model called the critical cluster model (CCM). An heuristic algorithm is described which is capable of producing efficient, high-quality solutions to this model in a GIS context. The paper concludes with an application of the method to Santa Barbara, California.
Cova et al. (Mon,) studied this question.