Evaluating Transportation Resilience
Evaluating The Transportation System’s Ability To Accommodate Diverse, Variable and Unexpected Demands With Minimal Risk
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Victoria Transport Policy Institute
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Updated
22 July 2008
This chapter explores the concept of resilience and the role that TDM strategies can play in creating a more resilient transportation system.
Resilience (also called reliability and risk management) refers to a system’s ability to accommodate variable and unexpected conditions without catastrophic failure, or “the capacity to absorb shocks gracefully” (Foster, 1993). Security refers to freedom from danger or fear, which is an important goal of resilience. These concepts have many implications for planning in general, and transportation planning in particular (Berdica, 2002; Husdal, 2005). Resilience can be evaluated at various levels.
· At an individual level it
means that people have Transportation Options needed to
satisfy their transportation needs even under unusual and unexpected
conditions, such as when their automobile breaks down, if they become
physically disabled, or their income decreases.
· At a community level it
means that a transportation system can safely and efficiently accommodate
unusual conditions, including construction projects, Emergencies,
Special Events, and gathering; and that the transport
system can provide Basic Accessibility to people with
special needs, including people with, low incomes, disabilities, or who do not
speak the local language.
· At a design level it means
that facilities can withstand extreme demands and unexpected conditions,
including major equipment failures, disasters and new technologies.
· At an economic level, it
means that transportation services can be provided if a particular resource,
such as petroleum, becomes scarce and expensive.
· At a strategic planning
level it mean that a transportation system can meet long-term economic, social
and environmental goals under a wide range of unpredictable future conditions (Sustainable Development).
Resilience reflects uncertainty, our inability to know what combination of conditions will occur in the future. If the future were predictable, Resilience would lose its importance: individuals and communities would simply need to plan for a single set of conditions. But since the future is unpredictable, it is necessary to plan for a wide range of possible conditions, including some that may be unlikely but which could result in significant harm if they are not anticipated.
The value of Resilience explains why people and communities are often willing to support transportation options and services that they currently do not use, in order to have them available if needed in the future, just as ship passengers value having life boats even when they are not being “used”. Economists call this “option value” (ECONorthwest and PBQD, 2002).
Resilience tends to increase if a system has diversity, redundancy, efficiency, autonomy and strength in its critical components. This allows the system to continue functioning if a link is broken, if a particular resource becomes scarce, if a particular decision-maker is unavailable, etc. It allows the system to accommodate a wide range of user needs and conditions.
Mobility can be an important strategy for increasing Resilience. Mobility permits movement away from adverse conditions or towards areas of greater need. For example, a common response to Disasters such as hurricanes and wars is to evacuate people from risky areas, and after such events occur there is often a need to bring in new resources to help with recovery efforts. An efficient transportation system is therefore an important part of a community’s overall resilience.
Resilience is affected by a system’s ability to collect and distribute critical information under extreme conditions. Resilience tends to increase if a system has effective ways to identify potential problems, communicate with affected people and organizations, and to Prioritize resources.
Resilience affected by a system’s ability to correct problems and perform repairs, even under extreme conditions. This means that critical components are self-correcting, repairable, redundant, autonomous (the failure of one component does not cause other components to fail), and fail-safe (i.e., if they fail they automatically shift to their most benign form). It means that decisions are incremental and reversible, so costs are minimized if a particular approach proves ineffective or dangerous.
Principles of Resilience (Foster, 1997)
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Social Compatibility
with diverse value systems. Capacity
to satisfy several goals. Equitable
distribution of benefits and costs. Generous
compensation for major losers. Accessibility System
Characteristics Diversity
of components. Functional
redundancy. Economic Incremental
funding. Wide
range of potential financial support. High
benefit-cost ratio Early
return on investments. Equitable
division of costs and benefits. Environmental Minimal
adverse impacts Replenishable
or extensive resource base. |
Timing Short
lead time and rapid response to stimuli. Open-ended
life span. Operational
Characteristics Efficient Reversible Incremental
operation. Autonomous
operation. Physical
Dimensions Not
site specific. Fine
grained and modular. Standardization No
esoteric components. Unique
skills unnecessary. Stable Fail-safe
detection. Early
fault detection. |
Many TDM strategies can improve transportation system Resilience by increasing transportation system diversity and flexibility, improving resource management, allowing resource Prioritization, improving communication, and by increasing the system’s overall efficiency.
Table 1 lists transportation system stresses, problems and risks, and TDM strategies that are particularly likely to address these problems and so increase system Resilience.
Table 1 Transportation Stresses and TDM
Solutions
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|
Individual or Household |
Community or Region |
|
Examples of transportation
system stresses, problems and risks. |
Temporary vehicle failure. Loss of driving privileges. Reduced income or increased
financial obligations. Physical disability or
difficulty communicating. Increased transportation
responsibilities, such as an increased need to chauffeur children or
visitors. Increased stress from
traffic and parking congestion. Loss of an accustomed
travel mode (such as a discontinued transit route). |
Major sport or cultural
event that attracts large crowds. Emergencies and disasters:
fire, earthquake, explosions, etc. Closure of a major bridge,
highway or rail line due to a crash, construction or other event. Influx of visitor or
refugees, particularly if they do not speak the local language or have other
special needs. Sudden change in the
availability of vehicle fuel or other critical resource. Increased travel demand due
to growth in population or economic activities. |
|
Strategies that can help
mitigate these problems and increase transportation system resilience. |
Location
Efficient Development |
Location
Efficient Development New
Urbanism (connected road networks) Pedestrian
and Cycling Improvements |
This table lists examples of stresses on the transportation system from individual’s and society’s perspectives, and TDM strategies that can help address those stresses.
Resilience can be evaluated based on a systems ability to provide its critical functions under variable, uncertain and extreme conditions. This involves identifying a system’s critical functions, its vulnerabilities, and ways to reduce vulnerabilities. Morlok and Chang (2004) discuss ways to quantify the ability of a transportation system to accommodate changing demands and traffic patterns. They describe two approaches, one of which holds traffic patterns constant, the second allows flexibility in traffic patterns, which reduces the amount of excess capacity needed at any point in the system to accommodate increased demand. This implies, for example, that the ability to shift travel routes, times, modes and destinations, through Transportation Demand Management, can be as important as increasing capacity to deal with sudden increases in peak demand. This type of analysis should involve more than simply contingency planning (considering “what would happen if…”) because it is not possible to predict every possible future condition. Below are specific steps in resilience planning. ECONorthwest and PBQD (2002) and Husdal (2003) describe methods for quantifying the value of an incremental change in resilience for incorporation into benefit/cost analysis.
The first step in this planning process is to define the extent of the system to be evaluated. For a transportation system this may include the transportation facilities and services in a particular jurisdiction or region, including those that connect outside of that area. All components of that system should be considered, including, for example, the pedestrian system, freight and package delivery systems, transportation for public services such as road maintenance and garbage collection, air travel systems, etc.
This involves identifying transportation activities and services are most valued to society. The list below is an example (Basic Accessibility).
This involves identifying various ways that a system’s components and requirements could fail or become inefficient. Below are some examples of potential problems to consider.
· A network link is broken,
such as a blocked sidewalk, bridge or roadway.
· A service fails, such as a
bus strike, or a motorist loses his or her ability to drive.
· A group of users has
difficulty walking or is unable to speak the local language.
· A critical resource becomes
scarce and expensive, such as a petroleum shortage.
· A common source of
information fails or provides false information, such as an incorrect
announcement of travel conditions by a radio station.
· A particular official,
technician or repair crew is unavailable during a crisis.
· A disaster requires
emergency transport of a large number of people, many who cannot drive, and
some with medical problems.
· A disaster causes extreme
traffic congestion on a particular roadway.
· A particular service is
discontinued due to inadequate demand, such as local bus or freight delivery
services.
The intent of this exercise is not to try to predict every possible problem that could occur, since it is impossible to know what combination of problems may occur. Rather, it is important to generalize the risks in order to find categories of vulnerabilities.
Find ways to reduce specific vulnerabilities, and incorporate Resilience principles into the planning and management of critical components of the transportation system. Below are examples of strategies that can increase Resilience.
· Increase transportation
system Diversity. Insure that there are opportunities
for people to walk, cycle, rideshare, carshare and travel by transit.
· Increase network redundancy
and connectivity (e.g., the number of roads and transit routes in an area).
· Increase facility design and
construction standards to withstand extreme conditions.
· Improve systems to identify
potential problems, including physical damage, unusual demands and new risks.
· Improve the ability to
communicate with transportation system users, including people with special
needs, even under unusual conditions.
· Establish ways to Prioritize transportation system resources (road space,
fuel, vehicle capacity) so it is available first to higher-value transportation
activities.
Contingency Based (or Responsive)
planning refers to the idea that the planning process must be able to change
over time in response to future needs. This involves the following steps:
1. Identify objectives (general things that you want to achieve) and targets (specific things that you want to achieve).
2. Identify various strategies
that can help achieve the objectives and targets. These can include both
projects that increase capacity and demand management strategies.
3. Evaluate the costs and
benefits of each strategy (including indirect impacts, if any), and rank them
according to cost-effectiveness or benefit/cost ratios.
4. Implement the most
cost-effective strategies as needed to achieve the stated targets.
5. After they are implemented,
evaluate the programs and strategies with regard to various performance
measures, to insure that they are effective.
6. Evaluate overall results
with regard to targets to determine if and when additional strategies should be
implemented.
Contingency-based planning addresses uncertainty by deploying solutions on an as-needed basis. For example, a transportation plan may identify 5 strategies to implement immediately, another 4 to implement in two years if stated targets are not achieved, and another 3 can be implemented further in the future if needed. This tends to be cost effective and flexible, because strategies are only deployed if they are needed, and additional strategies can be ready for quick implementation if unexpected changes create additional needs. This approach is ideal for medium and long-range transport and land use planning.
Resilience and security analyses are important for transportation planning. This can define design requirements (such as seismic standards for bridges) and service standards (such as transit service in lower-density areas). Many of the policies and practices that increase transportation system resilience are TDM strategies. Below are examples of ways to increase transportation system resilience and security.
· Value diversity, flexibility
and redundancy. As much as possible try to develop a multi-modal transportation
network. For example, if there are several possible ways to reduce traffic
congestion problems, favor the solutions that help improve transportation
system diversity.
· Avoid irreversible
decisions. For example, maintain railroad rights-of-way for possible future and
emergency uses.
· Use contingency-based
planning that identifies a wide range of potential solutions and implements the
most cost-effective strategies justified at each point in time, with additional
strategies available for quick deployment if needed in the future.
· Design transportation
facilities to withstand extreme conditions (earthquakes, storms, etc.).
· Incorporate security
planning as part of transportation planning. Perform user surveys, safety
audits and crime data reviews to identify and Address
Security Risks. Find ways to communicate with transportation system users
and include them in security planning.
· Include Emergency
Response as part of all transportation planning (local, regional, national,
transit, etc.). Consider disaster response as part of TDM planning, and TDM
solutions as part of disaster planning. Consider the widest possible range of
possible disasters and stresses on the transportation system, and consider the
widest possible range of possible solutions.
· Create a well Connected transportation system network that provides
multiple links to each destination.
· Encourage Transportation
Options, particularly for transportation modes and services that help
provide Basic Access. Support development of diverse
and competing transportation services, such as Ridesharing,
Telework, Delivery Services,
etc.
· Insure that transport
planning take into account people with special needs (physical disabilities,
low incomes, inability to speak the local language, etc.). Develop plans to
provide Basic Access to people with special needs, and
under unusual conditions.
· Develop effective ways to
maintain information and communication systems among transportation system
managers, staff and users under normal and extreme conditions. Develop ways to
warn travelers of problems and let travelers know their transportation options.
· Develop multiple,
overlapping communication systems that will continue to function if one
component fails.
· Develop ways to prioritize
the allocation of transportation system resources. For example, design systems
to allow emergency, public service and freight vehicles priority over general
traffic during emergencies. Maintain contingency plans to allocate fuel and
other resources in emergencies.
· Maintain ongoing
transportation systems evaluation to provide early detection of possible
problems and inefficiencies.
· Design critical components
of the transportation system to be fail-safe, self-correcting, repairable,
redundant and autonomous.
· Cross-train staff to perform
critical management and repair services.
· Encourage efficient use of
resources, including energy conservation and Accessible
land use.
· Develop Comprehensive
Planning that identifies the full impacts and vulnerabilities of a
transport system.
TDM Planning and Comprehensive Planning describes ways to improve current transportation planning practices, including consideration of resilience. Address Security Concerns describes ways to identify and reduce perceived risks to transportation system users. Special Event and Emergency Response planning indicates ways to prepare for events that require special transportation responses. Transportation Options describes how to evaluate the quality of transportation choices that are available in a community.
|
Two
hikers out in the woods encounter an angry bear. One stops to change from his
boots into running shoes. “What are you doing? You can’t outrun a bear!” says
his partner. “I
don’t need to outrun the bear. I just need to outrun you,” was the reply. |
The magnitude 6.8 Northridge (
This is an information sheet provided by the
Make
a Plan
Work
with your colleagues and counterparts in the police department, fire
department, health department, public buildings department, and emergency
management office to develop a plan that will be successful.
Review
your plan regularly and update it when your system changes or new threats
emerge
Plan
for the worst. Determine what you will do if…
· Normal communication systems
(television, web, radio, telecommunications) are not available.
· Electrical power is cut off.
· There are massive deaths or
injuries.
· There are air-borne chemical
or biological hazards.
Practice, Practice, Practice
Conduct
regular emergency/disaster drills (not just fire drills!) to keep skills sharp
and your plan up-to-date.
Build
interagency relationships; every level of transit leadership should personally
knows his/her counterparts in the agencies and organizations who will be responding
to an emergency situation.
Some Things that Really Matter
Put
the resources in place to execute your plan – people, equipment, facilities.
Identify
alternative means of transportation for the transit-using public in case one or
more of your primary modes is disabled.
Radio
communication capability is essential because cell phones are not reliable
during the emergencies; be sure you have multiple communication systems, in
case one or more is inoperative.
Conduct
criminal and credit background checks on every employee. Make sure every
employee has a photo identification and require that it be displayed at all
times.
Establish
Command Central
Immediately
set up a joint operations center so that your key responders can talk to each
other face-to-face and make joint decisions.
Although
it was not clear at the outset whether there was a terrible accident or a
terrorist incident, the command center leadership made the decision to respond
to the situation as a terrorist attack. As a result, the NYC transit authority
immediately evacuated all trains, passengers and transit employees from the
Improvise!
Be
ready and willing to improvise; even a good plan can’t anticipate everything.
NYC Transit made the decision to let everyone leave the city for free; this
decision made the evacuation process quicker and built tremendous goodwill with
the public.
Communicate
with the Public
Use
your website to communicate your service plans and availability with the public
on a real-time basis.
NYC
Transit has been getting 10 million hits a day, compared to a usual 200,000
hits, and updates its site every 2 hours even if no substantive changes to
service have been made.
Work
with local television and radio stations to get information about closings and
alternative routes to the public
Restore Public Confidence
Increase
law enforcement visibility; put a uniformed officer on every train, if
possible, to reassure the public and deter potential threats.
Tell
people – with brochures, ads, and announcements – how they can help enhance
security.
Following
the September 11, 2001 terrorism attacks in downtown
APTA (2001), Checklists For Emergency Response Planning And System Security, American Public Transit Association (www.apta.com/services/safety/checklist.htm).
Katja Berdica
(2002), “An Introduction to
Road Vulnerability: What Has Been Done, Is Done and Should Be Done,” Transport
Policy, Vol. 9. No. 2 (www.elsevier.com/locate/tranpol),
April 2002, pp. 117-127.
Stephanie Chang and Nobuoto Nojima (2001), “Measuring Post-Disaster Transportation System Performance: The 1995 Kobe Earthquake in Comparative Perspective,” Transportation Research A, Vol. 35, No. 6 (www.elsevier.com/locate/tra), July 2001, pp. 475-494.
Thomas J. Cova and Steven Conger (2004), “Transportation
Hazards,” Handbook of Transportation Engineering, (M. Kutz Editor)
McGraw Hill (www.mcgraw-hill.com),
pp. 17.1-17.24; available at www.geog.utah.edu/~cova/cova-conger-teh.pdf.
J. Joseph Cronin, Roscoe Hightower and Michael Brady (2000), “Niche Market Strategies; The Role of Special Purpose Transportation Efforts in Attracting and Retaining Transit Users” Journal of Public Transportation, Vol. 3, No. 3 (www.cutr.eng.usf.edu), pp. 63-86.
ECONorthwest
and PBQD (2002),
Estimating the Benefits and Costs of Public Transit Projects, TCRP Report 78, TRB (www.trb.org); available at http://gulliver.trb.org/publications/tcrp/tcrp78/index.htm.
Reid
Harold Foster (1997), The Ozymandias Principles,
Southdowne Press,
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FTA Safety and Security Website (http://transit-safety.volpe.dot.gov), by the U.S. Federal Transit Administration, provides information on transit safety and security issues, including disaster preparedness and response.
Antoine Hobeika, Siamak Ardekani and Alejandro Martinez-Marquez (1987), Transportation Problems and Needs in the Aftermath of the 1985 Mexico City Earthquake, Natural Hazards Research and Applications Information Center (www.colorado.edu/hazards).
Jan Husdal (2004), Why Reliability And Vulnerability Should Be An Issue In Road Development Projects, first published in Samferdsel: Journal of the Norwegian Institute of Transport Economics (www.toi.no/samferdsel); at (www.husdal.com).
Jan Husdal (2005), The Vulnerability Of Road Networks In A Cost-Benefit Perspective, TRB 84th Annual Meeting (www.husdal.com/gis/trb2005_final.pdf).
Natural Hazards Research and Applications Information
Center,
Genevieve Giuliano and Jacqueline Golog (1998), “Impacts of the Northridge Earthquake on Transit and Highway Use,” Journal of Transportation Statistics, Vol. 1, No. 2 (www.bts.gov), May 1998, pp. 1-20.
Erik Jenelius, Tom Petersen and Lars-Goran Mattsson (2006), “Importance and Exposure in Road Network Vulnerability Analysis,” Transportation Research A, Vol. 40, Issue 7 (www.elsevier.com/locate/tra), Aug. 2006, pp. 537-560.
Todd Litman (1999), First Resort; Resort Community Transportation Management, VTPI (www.vtpi.org); available at www.vtpi.org/resort.pdf.
Todd Litman (2005), Lessons From Katrina and Rita: What Major Disasters Can Teach Transport Planners, Victoria Transport Policy Institute (www.vtpi.org); available at www.vtpi.org/katrina.pdf.
Harvey J. Miller (2003), “Transportation and Communication Lifeline Disruption,” in S. L. Cutter, D. B. Richardson and T. Wilbanks (eds.) The Geographic Dimensions of Terrorism, Routledge, pp. 145-152, available at www.geog.utah.edu/%7Ehmiller/papers/lifelines.pdf.
Edward K. Morlok and David J. Chang (2004), “Measuring Capacity Flexibility of a Transportation System,” Transportation Research A, Vol. 38, No. 6 (www.elsevier.com/locate/tra), July 2004, pp. 405-420.
Nancy W. Okasaki (2003), “Improving Transportation Response and Security Following a Disaster,” ITE Journal (www.ite.org), August 2003, pp. 30-32.
Nada D. Trout and Gerald L. Ullman (1997), “A Special Event Park-and-Ride Shuttle Bus Success Story,” ITE Journal (www.ite.org), December 1997, pp. 38-43.
Transportation Security Website (www4.trb.org/trb/homepage.nsf/web/security)
provides information developed by the Transportation Research Board and
USDOT (2005), Effects Of Catastrophic Events On
Transportation System Management And Operations:
This
Encyclopedia is produced by the Victoria Transport Policy Institute to help
improve understanding of Transportation Demand Management. It is an ongoing
project. Please send us your comments and suggestions for improvement.
Victoria Transport Policy Institute
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