Prioritization of security measures against terrorist threats to public rail transport systems using a scenario-based multi-criteria method and a knowledge data base

Public rail transport systems (PRTS) are open systems with many entrances and exits. They
carry a large number of passengers every day, thus being an attractive target for terrorists.
Terrorists attack PRTS primarily (a) to gain great public and media attention due to large
number of casualties to be expected and (b) to cause severe economic damages by
interrupting those systems. To reduce the risk or mitigate the consequences of terrorist
attacks, security measures need to be introduced. The extensive range of possible scenarios
and related measures make the selection of appropriate measures difficult. Furthermore, not
all possible measures might meet the expectations of passengers, public authorities and/or
operators of PRTS. This paper presents a research in progress on an integrated approach to
support the decision-making process in terms of prioritizing security measures. It is based on
a knowledge database, case-based reasoning (CBR) and multi-criteria decision analysis
(MCDA).