Tag Archives: transportation resilience

Resilience X 10

Leave a reply
Revised on: 2015-11-07

Transport network resilience has 10 properties. So says Pamela Murray-Tuite in her 2006 article A Comparison of Transportation Network Resilience Under Simulated System Optimum and User Equilibrium Conditions. I had completely forgotten about these 10 properties, until I came across them again in an 2013 article on Safeguarding critical transportation infrastructure by Joseph S.Szyliowicz. However, there’s more to the story than just this…

Too many posts to remember

The reason for looking deeper into Szyliowicz’ paper in the first place was that I had searched academic literature databases for references of my papers to see whether any of the papers I had written was making an impact. In Szyliowicz’ paper I found that he had cited a blog post I wrote in 2011, about The UK Transport Network Resilience…and I.  Looking it it up, I discovered that I had mentioned Murray-Tuite’s ten properties in my own blog post 4 years ago. So why did I forget about them? Too many posts to remember, perhaps. Besides I never mentioned Murray-Tuite as a reference in the post or as a worthy paper in my literature review list, otherwise I might have remembered her, I guess. I only copied Murray-Tuite’s definitions from the report I was reviewing in that blog post.

Not her own

Anyway, upon re-reading the article by Murray-Tuite I realised the ten properties were not all her creation, but taken from other authors. Six out of ten came from a 2003 paper on Urban Hazard Mitigation: Creating Resilient Cities by David Godschalk. Ouestions of originality aside, she does deserve credit for taking the concept of resilience from the realm of urban planning and adopting it to the realm of transport planning. Moving ideas from one realm to another is not always straightforward. Murray-Tuite also deserves solid credit for describing and quantifying four of these properties with regard to transport networks.

Ten properties of resilience

According to Murray-Tuite, the ten properties of resilience in transport network are redundancy, diversity, efficiency, autonomous components, strength, adaptability, collaboration, mobility, safety, and the ability to recover quickly.

Redundancy – the transport system contains a number of functionally similar components which can serve the same purpose and hence the system does not fail when one component fails (for example, a number of similar routes are available with spare capacity).
Diversity – the transport system contains a number of functionally different components in order to protect the system against various threats (for example, alternative modes of transport are available).
Environmental Efficiency – a transport system which is environmentally efficient will be more sustainable, and capacity is less likely to be constrained due to environmental reasons.
Autonomy – the components of the transport system are able to operate independently so that the failure of one component does not cause others to fail (for example, can the transport system operate safely in the event of a power cut?).
Strength – the transport systems ability to withstand an incident (for example, how extreme a flood event can the system cope with?).
Adaptability – or flexibility, can the transport system adapt to change and does it have the capacity to learn from experience (for example, an area-wide traffic management system can adapt to differing traffic conditions).
Collaboration – information and resources are shared among components and/or stakeholders (for example, contingency plans in the event of an emergency and the ability to communicate with system users).
Mobility – travellers are able to reach their chosen destinations at an acceptable level of service.
Safety – the transport system does not harm its users or expose them, unduly, to hazards.
Recovery – the transport system has the ability to recover quickly to an acceptable level of service with minimal outside assistance after an incident occurs.

The first six are taken from Godschalk, and mobility is taken from the page called Evaluating Transportation Resilience on the Victoria Policy Institute website. On a sidenote, some of my works have also been included there, namely, The vulnerability of road networks in a cost-benefit perspective, a paper I presented at TRB in 2005.

Seven properties of resilience

In the opriginal paper, if it can be put that way, Godschalk actually lists seven properties of resilience. The seventh, interdependence, was apparently not found applicable by Murray-Tuite. I wonder why, because Godschalk defines this property as such

Interdependent: with system components connected so that they support each other

In my opinion a resilient transport network should definitely be interdependent in the way that Godschalk describes it.

On another sidenote, Godschalk also refers to the Victoria Policy Institute website as one of his references. However, given the year Godschalk wrote his paper, that website and their TDM Encyclopedia was probably still in its infancy.

The resilient city

One paragraph that really struck a cord with me is where Godschalk describes his view of the ideal resilient city:

Resilient cities are constructed to be strong and flexible, rather than brittle and fragile. Their lifeline systems of roads, utilities, and other support facilities are designed to continue functioning in the face of rising water, high winds, shaking ground, and terrorist attacks. Their new development is guided away from known high hazard areas, and their vulnerable existing development is relocated to safe areas. Their buildings are constructed or retrofitted to meet code standards based on hazard threats. Their natural environmental protective systems are conserved to maintain valuable hazard mitigation functions. Finally, their governmental, non-governmental, and private sector organizations possess accurate information about hazard vulnerability and disaster resources, are linked with effective communication networks, and are experienced in working together.

In some way that is exactly what I am trying to do in my day job as a Resilience Adviser, with the lifeline system of roads being the starting point.

Resilience and redundancy

Going back to Szyliowicz, his paper focuses on the various facets of resilience, although most of the paper is spent on what the US has done or not done or perhaps should have done since 9/11 to increase resilience in the transport infrastructure. That said, I do sense that he is ever so slightly inclined towards redundancy as a key ingredient in resilience. Moreover, he credits me with quoting transit planning consultant Bob Bourne for saying that

‘‘Redundancy is not favored by policy makers and can add to costs. However, a system with excess capacity will perform well in times of crisis and will provide additional service during normal times.’’(cited in Husdal, 2011).

Honestly, I never mentioned Bob Bourne in my blog post on resilience. I even checked the web archive to see if it was ever there. What I did find though, with the help of Google, was a 2011 blog post by transit planning consultant Jarret Walker, who cited Bob for those exact words. So much for due diligence…

Thirty-one properties of resilience

On a final note, Godschalk in his paper references Harold D. Foster and his book The Ozymandias Principles: Thirty-one Strategies for Surviving Change. That book features no less than 31 dimensions of resilience, divided by social, physical, environmental, operational, economic, systems and time dimension. It’s not an easy book to get one’s head around, but one day I will present the book on this blog

Reference

Murray-Tuite, P. (2006) A Comparison of Transportation Network Resilience Under Simulated System Optimum and User Equilibrium Conditions. Proceedings of the 38th Conference on Winter Simulation, Monterey, CA, USA — December 03 – 06, 2006 DOI: 10.1109/WSC.2006.323240

Godschalk, D. (2002) Urban Hazard Mitigation: Creating Resilient Cities. Nat. Hazards Rev., 4(3), 136–143 DOI: 10.1061/(ASCE)1527-6988(2003)4:3(136)

Szyliowicz, J. (2013) Safeguarding critical transportation infrastructure: The US case. Transport Policy, Volume 28, Pages 1-122 (July 2013) DOI: 10.1016/j.tranpol.2012.09.008

Author links

Related posts

Vulnerability and resilience of transport systems

Leave a reply
Revised on: 2015-09-16

I’ve been away from academia for the last three years, and in my efforts to catch up with the latest research in transport-related vulnerability and resilience I decided to start with the most recent papers, and track my way backwards using the references cited as a potential guideline.  This paper by Lars-Göran Mattsson and Erik Jenelius on Vulnerability and resilience of transport systems – A discussion of recent research seemed like a good start. What first struck me with this paper not the extesive reference list, but a figure the authors used.

Not the first time

The reason why the figure struck me is that from time to time there are similar figures that appear in a number of different papers, and as a researcher I am always intrigued to find the original source and who came up with this figure in the first place. I first saw this figure it in 2007 when I reviewed Youssi Sheffi’s book The Resilient Enterprise. There they describe what they call a “disruption profile”, which looks something like this:

Sheffi 2004

Going back in time 20 years, a very similar figure was used in Rausand and Einarssons paper from 1997 on  An Approach to Vulnerability Analysis of Complex Industrial Systems, showing how an accidental event produces a consequence scenario, a disruption that tests the systems survivability:

Einarsson and Rausand 1997

Similarly, Mattson and Jenelius use a figure they call “Effects of decision-making on resilience”, which relates to same subject, but has a different approach:

Mattsson and Jenelius 2015

Obviously all figures address the same issue, that is the effect of disruptive events on system function (Mattson an Jenelius) or supply chain performance (Sheffi). The difference is that while Sheffi integrates  mitigation and adaption in the shape of his one curve, Mattson and Jenelius specifically show how much mitigation and adaption contribute to changing how the curve bends.

So, while the principle behind the figure may not be original, the way that Mattson and Jenelius put it to use in their paper is definitely ground-breaking, because it clearly shows how mitigation can lessen the impact of an event and how resilience can be an expression of how the organisation returns to normal after an event.

Mitigation and adaptation

Now, mitigation and adaptation are two very intriguing concepts here. Essentially, risk management is all about mitigation, whereas adaptation lays the groundwork for resilience. In my world, where risk management is very much based on the bow-tie principle, mitigation is primarily concerned with the left side of the bow-tie, reducing the likelihood of events occurring. I called it mitigative actions and contingent actions respectively.

Bow-tie

Mitigation, where I come from, is mostly concerned with prevention. However, as I am now gradually discovering, mitigation addresses the whole bow-tie, both the causes on the left side and the consequences on the right side. Resilience then, looks further to right of the bow-tie, and how the organisation tries to deal with the long-term impacts of an event. That is a new point of view that I hadn’t thought about, or rather, I had thought about it, but I haven’t able to put it into a figure as brilliantly as Mattsson and Jenelius have done in this paper. It appears to me now that the bow tie is only about preparedness, response, and recovery. By adding adaptation to those three we also add resilience.

First a vulnerability analysis, then resilience

The authors go on to discuss the current literature on resilience and settle for Hollnagel’s four cornerstone definition: knowing what to do, what to look for, what to expect, and what has happened. Vulnerability analysis is an important prerequisite for adequate proactive actions.

Mattsson and Jenelius (2015) Resilience

Resilience, so Hollnagel, can be defined as:

the intrinsic ability of a system to adjust its functioning prior to, during, or following changes and disturbances, so that it can sustain required operations under both expected and unexpected conditions

That is an interesting definition, because in my world, as I wrote about in my post on how road vulnerability is analysed in Norway, vulnerability is seen as

the degree of ability that an object has to withstand the effects of an (unwanted) event and to resume its original condition or function after that event.

Here the negativity of vulnerability (as in susceptibility to fail) is defined in a positive way, by saying that the better the ability to withstand, the lesser the vulnerability. So actually, my definition of vulnerability in a sense is not too far from Hollnagel’s definition of resilience. Another new discovery for me.

Conclusion

This is a very interesting paper that combines a qualitative introduction with a quantitative argumentation when it comes to exemplifying their discourse. The paper also contains a number of promising references related to resilience that I plan to discuss in a later post.

Reference

Mattsson, L-G., Jenelius, E (2015) Vulnerability and resilience of transport systems – A discussion of recent research. Transportation Research Part A 81 (2015) 16–34. DOI:10.1016/j.tra.2015.06.002

Author links:

Related posts


Transport infrastructure resilience

Leave a reply
Revised on: 2015-09-26

Is it possible to devise a simple framework for assessing the resilience of the transport infrastructure? The answer is Yes, and the New Zealand Transport Agency has done so. That said, it is not a “simple” framework. It is comprehensive, it is academically well-founded, it is practical, but it is not easy to put into use. Nonetheless, New Zealand has done that, too. In my opinion, it is something  many countries can learn from.

My own struggles

I came across this report on Measuring the resilience of transport infrastructure, published by the NZ Transport Agency, while trying to come up with a similar means of measure for the Norwegian road network. The measure would be put into use (among many other criteria) for prioritising investment projects in our National Transport Plan, a ten-year-plan that is revised every four years and that outlines how the Government intends to prioritise resources within the transport sector. The emphasis here is on “outlines” and “intends”, since the plan is not a commitment, merely an intention, and funding has to be allocated and voted upon by the parliament every year. Still, the four national agencies that are responsible for air, sea, rail and road transport in Norway spend considerable resources for finding projects, evaluating them and prioritising them, just to see the politicians then preferring the politically attractive projects over the economically attractive projects, as I wrote in a post some time back on why the world’s richest country has the world’s worst roads.

Resilience defined

Anyway, back the New Zealand report, and the reason for mentioning it on this blog, is the thoroughness with which the subject of resilience is described, and then narrowed down into two components: technical resilience and organisational resilience.

But before I get to that point, what enticess me most of all is their definition of resilience:

The concept of resilience is wider than natural disasters and covers the capacity of public, private and civic sectors to withstand disruption, absorb disturbance, act effectively in a crisis, adapt to changing conditions, including climate change, and grow over time.

As the report states, this definition rightly acknowledges that the service the infrastructure delivers will be disrupted, due to damage to the infrastructure; however, the service is able to reduce the possibility of failure, adapt and recover from a disruptive event and/or gradual external changes over time.

This reminds me of one my previous posts, about resilient organisations. There, resilience is about a company’s capacity to benefit from unlikely events, events which could have turned into threats, but instead were turned into opportunities. It is about the capacity to take advantage of serendipity, to take advantage of involuntary sagacity.

Two dimensions of resilience

The reseach report goes through a number of approaches towards resilience, citing academic references and relevant literature, and focuses on the key point, that resilience has two dimensions: organisational and technical:

Technical resilience: The ability of the physical system(s) to perform to an acceptable/desired level when subject to a hazard event.

Organisational resilience: The capacity of an organisation to make decisions and take actions to plan, manage and respond to a hazard event in order to achieve the desired resilient outcome.

I think this makes sense. While you can invest in strengthening your infrastructure techincally, this will not make you any more resilient unless the organisation(s) responding to an event are skilled, prepared and trained towards it.

Within these dimensions the authors describe underlying principles of both technical and organisational resilence:

Technical:

Robustness: the ability of elements, systems and other units of analysis, to withstand a given level of stress or demand without suffering degradation or loss of function

Redundancy: the extent to which elements, systems, or other infrastructure units exist that are substitutable, in the event of disruption, degradation, or loss of functionality.

Safe-to-fail: the extent to which innovative design approaches are developed,  recognising that the possibility of failure can never be eliminated.

Organisational:

Change readiness: the ability to sense and anticipate hazards, identify problems and failures, and to develop a forewarning of disruption threats and their effects.

Networks: the ability to establish relationships, mutual aid arrangements and regulatory partnerships, understand interconnectedness and vulnerabilities across all aspects of supply chains and distribution networks.

Leadership and culture: the ability to develop an organisational mind-set/culture of enthusiasm for challenges and opportunities.

As I see it, the authors have captured mots if not all of which that goes into resilience.

Overall resilience score

Based on the dimensions and principles the authors devise a resilience assessment framework that comes up with a final overall resilience score: Very High, High, Moderate and Low resilence.

Complicated? Maybe. Comprehensive? Yes.

Reference

Hughes, JF and K Healy (2014) Measuring the resilience of transport infrastructure. NZ Transport Agency
research report 546. 82pp

Author links

Download

nzta.govt.nz: Measuring the resilience of transport infrastructure

Related posts

husdal.com: Resilient organisations

The UK Transport Network Resilience…and I

Leave a reply
Revised on: 2015-11-07

For a budding and even for a seasoned researcher, nothing is more rewarding than to have one’s publications cited. Sometimes that happens in the unlikeliest of places. Or maybe this place is not so unlikely after all, given the main themes of my 10 years of research: supply chain risk, business continuity, and transportation vulnerability. It’s the latter that has caught the attention of a consultancy in the UK when preparing a report for the UK Highways Agency. The report, dated 2010 and titled Network Resilience and Adaptation, assesses and details in great depth the vulnerability and resilience of the transport infrastructure in the East of England and displays it using a GIS. “My” contribution, if I may call it that, is in the literature review section of the report, where definitions and perspectives on vulnerability, resilience and related terms are discussed. Frankly,  I had almost forgotten about these definitions, since I wrote them in a paper in 2004, but it’s nice to see that they still make an impact.

Continue reading →

Transportation Resilience

1 Reply
Revised on: 2015-11-10

There hasn’t been a proper literature review on my blog for a while, but this post will put it right again, hopefully. Moreover, there hasn’t been a post on transportation for a while either, and this post will put that right, too.  The other day I came across Transportation security and the role of resilience: A foundation for operational metrics, a recent article by Andrew Cox, Fynnwin Prager and Adam Rose that presents a framework for evaluating transportation resilience, including the important role of perceptions in potentially amplifying security risks. With transportation being a major part of any supply chain this article also presents a framework for evaluating supply chain security and resilience. Based on the July 2005 terrorist attacks in London this paper not only develops a predictive resilience measures but also describes various strategies at the macro, micro and meso level.

Continue reading →