  Several simulation environments exist for the simulation of large-scale
evacuations of buildings, ships, or other enclosed spaces. These offer
sophisticated tools for the study of human behaviour, the recreation of
environmental factors such as fire or smoke, and the inclusion of architectural
or structural features, such as elevators, pillars and exits. Although such
simulation environments can provide insights into crowd behaviour, they lack
the ability to examine potentially dangerous forces building up within a crowd.
These are commonly referred to as crush conditions, and are a common cause of
death in emergency evacuations.
  In this paper, we describe a methodology for the prediction and mitigation of
crush conditions. The paper is organised as follows. We first establish the
need for such a model, defining the main factors that lead to crush conditions,
and describing several exemplar case studies. We then examine current methods
for studying crush, and describe their limitations. From this, we develop a
three-stage hybrid approach, using a combination of techniques. We conclude
with a brief discussion of the potential benefits of our approach.
