Resilience Management of Transport Infrastructure and Demand: the Case of the Athens Metro
Alexandros Deloukas, Attiko Metro S.A., Emy Apostolopoulou, Attiko Metro S.A.
The static and dynamic resilience of transport infrastructure and demand is investigated using the example of the Athens transport system with an emphasis on the metro network. The related pilots refer to large-scale malevolent attacks.
The EU-funded project ‘RESilience management guidelines and Operationalization appLied to Urban Transport Environment (RESOLUTE)’ addresses critical components of urban transport systems (UTS) in view of safety and security needs. The project aims the development of European resilience management guidelines (ERMG) adapted to UTS as well as a resilience model for collaborative emergency responses. The ERMG validation will be executed i.a. through specific Athens metro pilots.
The threat type of the metro pilots pertains to large-scale malevolent attacks (bomb blast, CBRNE exposure). The metro lines comprising 36 kms & 37 stations, carrying 210 mi. passengers p.a., constitute the backbone of the Athens urban transport system. Threat scenarios refer to partial or full closure of affected lines in the post-attack phase. Failure propagation among system components is investigated. The attack risk is conceptualised as the potential that the threat will successfully exploit vulnerabilities within the metro system and therefore result in harmful consequences for the public and the operator. Specific weaknesses refer i.a. to the scale and the topology of the metro network whereas external vulnerabilities to the road corridor connectivity with urban sectors.
The static resilience of the UTS demand is related to the UTS robustness –i.e. maintaining system function after the shock without metro infrastructure restoration. The efficiency of modal substitute strategies (bus bridging, permission of HOV-only use) is assessed with the use of the Attiko Metro multi-modal transportation model. The retraction of spare buses from proximal depots and scheduled bus lines is a critical strategy component. Metro-bus-metro and metro-longer bus leg bridging are options considered. Effective policies mitigate the transport capacity degradation during the disruption.
The dynamic resilience of metro demand aims to re-establish the ‘normal’ level of demand as briefly as possible. This presupposes fast repair and restoration of the infrastructure. Strategies of reducing the perceived risk by the adaptively minded public are discussed. Both cognitive and affective dimensions of risk judgment are acknowledged. The previous experience of less (9/11, London 7/2005) and more resilient behaviour (Madrid 3/2004, Tokyo 3/1995) are discussed. The risk threshold of the Athenian public with respect to a potential strike is assessed through a Willingness-To-Accept risk valuation. The experiment comprises a panel of 550 face-to-face structured interviews and provides (stated only) evidence on the (a) level of metro demand alteration due to the dread risk, (b) segmentation of demand response (discretionary vs. compulsory travel), (c) temporal rate of demand alteration (short- vs. mid-term impact). Transportation model runs with extended generalised cost functions incorporate a cost component of perceived risk at a time. Scenario comparisons estimate the speed of metro demand recovery.
The paper is a novel contribution to the resilience of urban transport systems.
Association for European Transport