
270 ◾ Risk Assessment and Security
7.7.1 Risk Estimation and Risk Acceptability
Based on the event tree analysis for a terrorist attacks against the rail system for
transshipment of bomb materials, as shown in Figure 7.4a, the comparison of risk
estimation and risk acceptability is presented in Table 7.10. e detailed incremen-
tal risk acceptability quantications and results are presented in Table 7.11. Finally,
the comparison of strategic alternatives for US intelligence and rail system defense
against terrorism is presented in Table 7.12.
US intelligence is the gist to all the eort for homeland and critical infrastruc-
ture protection and defense. ...