Transport Network Vulnerability: a Method for Diagnosis of Critical Locations in Transport Infrastructure Systems

Considerations of critical infrastructure are now a major concern in Australia as in many other countries. The concern stems from a variety of causes, including the state of development, condition and level of use of existing infrastructure systems, especially transport networks; difficulties associated with public sector provision of new infrastructure; publicprivate partnership arrangements for infrastructure provision; and perceptions of risks and threats to infrastructure from both natural disasters (e.g. floods, fire or earthquake) and from human malevolence such as acts of sabotage, war or terrorism. The Australian Federal Government has defined critical infrastructure as ‘that infrastructure which if destroyed, degraded or rendered unavailable for an extended period, will significantly impact on social or economic well-being or affect national security or defence’ (Attorney-General’s Department, 2003). A pertinent question is then how to identify critical locations in an infrastructure network. For example, the road transport network is large, wide and diverse in nature. Are there particular locations or facilities in that network where loss or degradation of certain road sections (links) will have significant impacts? How should such impacts be assessed?