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Developing a Methodology for Road Network Vulnerability

Analysis

Erik JeneliusDiv. of Transport and Location Analysis

Dept. of Transport and EconomicsRoyal Institute of Technology (KTH), Stockholm

Nectar Cluster 1 Seminar, 12th – 13th May 2006, Molde University College

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Summary

• Description of new project“Vulnerability Analyses of Road Networks”- Problem- Aim- Method

• Review of pilot study (Jenelius et al, 2006)

- Concepts- Application examples

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Why study road network vulnerability?

• Welfare of citizens• Development and competitiveness of industry• Efficient commuting• Efficient logistics (just-in-time)• Regional development• Infrastructure repairs• …

• Which roads are particularly important?• Which regions are particularly exposed?

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New Project: Aims

• Develop indicators of vulnerability and methods by which the effects of various actions could be assessed

• Develop tools to describe the functioning of the road system for the communication with the business community, regional representatives and different groups of users

• Connect to cost-benefit analysis so that it will be possible to analyse how the vulnerability could be reduced given limited budget for investments, operations and maintenance.

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Method

• Primarily develop ideas from previous pilot study (Jenelius et al, 2006)

• Develop a new modelling tool- increase speed- include possibilities to handle scenarios (storms, floods, …)- integrate with GIS for visualization and scenario building

• In case of available data and time:- model and estimate weakness of links from historical incident data

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Desired outcomes

• Perform study for the whole Swedish road network

• Study sub-network that complies with certain bearing capacity

• Study specific group such as timber transports• Scenario models:

- thaw, floods, extreme weather, accidents, …

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What is vulnerability?

• “A susceptibility to incidents that can result in considerable reductions in road network serviceability” (Berdica, 2002)

• Vulnerability contains probability and consequences (exposure)

• Possible vulnerability measures:P(Q > q): probability that consequences Q above threshold q (Holmgren, 2006)

E(Q): expected consequences

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Consequences: Importance and exposure

• The weakness of a link is the probability of a failure

• The importance of a link are the consequences of failure

• The criticality is a combination of weakness and importance

• The exposure of a region to a certain harmful event is the consequences of that event for that region

• Link k important to region R Region R exposed to failure of link k

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Measuring importance and exposure

• Measured as:

increased generalised travel cost

+ unsatisfied demand

• Other possible measures:

decreased potential accessibility

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Global link importancefor the whole network

• E4 European highway• Most important link in

High Coast region

Minutes/OD pair0 - 0.330.33 - 1.311.31 - 2.722.72 - 5.445.44 - 10.76

0 200 400 Kilometers

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Demand weighted link importancefor the whole network

• Short city roads, E4• Local and regional traffic• Most important link

in GävleVehicle min/veh

0 - 0.020.02 - 0.080.08 - 0.190.19 - 0.450.45 - 1.22

0 200 400 Kilometers

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Unsatisfied demand related link importancefor the whole network

• Roads near the coast• Boundary effects• Most important link

in Gävle• Sensitive measure

Unsatisfied veh/total00 - 0.00050.0005 - 0.00170.0017 - 0.00360.0036 - 0.00840.0084 - 0.024

0 200 400 Kilometers

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Worst-case scenario: most important link closedDemand-weighted municipality exposure

• Local density important

• Northwestern parts the most exposed Vehicle min/veh

0.5 - 3.83.8 - 5.25.2 - 11.811.8 - 24.124.1 - 83.7

0 200 400 Kilometers

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Worst-case scenario: most important link closedUnsatisfied demand-relatedmunicipality exposure

• Northwestern region highly exposed

• Middle region unexposed Unsatisfied veh/total

0.001 - 0.0080.008 - 0.050.05 - 0.1020.102 - 0.2810.281 - 0.833

0 200 400 Kilometers

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