  Evacuation planning and scheduling is a critical aspect of disaster
management and national security applications. This paper proposes a
conflict-based path-generation approach for evacuation planning. Its key idea
is to generate evacuation routes lazily for evacuated areas and to optimize the
evacuation over these routes in a master problem. Each new path is generated to
remedy conflicts in the evacuation and adds new columns and a new row in the
master problem. The algorithm is applied to massive flood scenarios in the
Hawkesbury-Nepean river (West Sydney, Australia) which require evacuating in
the order of 70,000 persons. The proposed approach reduces the number of
variables from 4,500,000 in a Mixed Integer Programming (MIP) formulation to
30,000 in the case study. With this approach, realistic evacuations scenarios
can be solved near-optimally in real time, supporting both evacuation planning
in strategic, tactical, and operational environments.
