A review of evacuation models used worldwide
for a range of hazards, (including technological hazards such as
nuclear accidents), has been carried out as part of Task 17. This
review is available as the
Technical Note entitled "Review of evacuation rescue methods and
models". The
review found that in general the evacuation models available could be
grouped
as follows:
- Traffic simulation models;
- Evacuation behaviour models;
- Time-line/critical path
management diagrams.
Traffic simulation
models comprise either
micro, meso or macro types of traffic stream simulation, with simple,
static or
dynamic types of traffic route assignment. Micro-simulation
is based upon detailed simulation of individual vehicle movements.
Meso-simulation is based on movements of traffic streams coupled to
relatively
simple evacuee route selection logic. Dynamic traffic assignment
(macro-simulation) pays more attention to the
route selection process and relies upon a more aggregate representation
of
traffic as a series of flows, while attempting to match this demand for
road
space to the capacity of the highway system’s links and intersections.
Detailed
network evacuation models allow the planner to experiment with a
selection of
alternative evacuation routes, destinations and evacuee response rates
as a
means of determining effective evacuation strategies. This process of
generating plans and
expected
network clearance (evacuation) times currently requires a five-step
process,
involving the creation and calibration of:
- A traffic generation sub-model;
- A traffic departure time
(traffic loading rate) sub-model;
- A destination selection
sub-model;
- A traffic route selection
sub-model;
- A user specified plan set-up,
analysis and revision procedure.
A time-line diagram
shows the
critical path of emergency response for flood evacuation. This method
has the
advantage of showing how
critical the relationship is between flood prediction, evacuation
decisions,
emergency service response and community actions and the passage of
time in a
flood. The resulting time-line can then
be used to show participants in a flood planning or response activity
what has
to be done, when it has to be started, and approximately how long it
might take
during the flood scenario analysed (FLOODsite,
2006).
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