This week I'd like to introduce an idea that I don't think is all that popular in the practice of planning: systems theory. Understood through system dynamics, what we are talking about it a way of understanding how the world works. Often applied to ecosystems and physiology (including human), systems theory can be applied in a wide variety of arenas including cities. System dynamics is intended to provide a model of how systems work in place of standard economic models. These system dynamics models help to facilitate systems thinking. I'd also like to look at systems theory applied to an example urban problem and explain why it's important for planners (as well as citizens) to begin using systems thinking when contemplating problems that face urban areas.
To introduce these ideas with a short history: System theory began with Ludwig von Bertalanffy's book on the subject, first published in 1968. Among its precursors are Karl Marx and Emile Durkheim's work in the nineteenth century, and cybernetics, a related field. Systems Philosophy was part of a new group dubbed 'Systemics', which included the domains of (systems) technology and science as well. System Dynamics is a way of modeling complex, nonlinear systems that include stocks, flows, and feedback loops. This was done with software developed in the 1950s and 60s for industrial purposes but in 1969 the book Urban Dynamics introduced the idea that systems thinking could be applied to urban issues. Systems thinking then, is an approach to understanding the world around us by not just looking at the component parts, but how they interact and affect each others' behavior.
Cities are systems. Much as we now recognize that the biological world is full of interconnected systems called the ecosystem, we should now also realize that there is a mirror of that world in the city. Urban systems are composed of people and organizations of people. Towns and cities are made of both constituent parts: businesses, churches, schools, political organizations, social groups, etc. as well as the interconnected stocks and flows that make for complex systems. All of these parts interact and create communities that themselves overlap and interact to form neighborhoods, towns and cities. Understanding cities as systems helps us to understand the reverberant consequences of our actions in urban planning.
Having a particular interest in transportation issues, I wanted to look at a popular example describing, in brief detail, how a systems perspective might help us understand the dynamics at work. The example being the popular phrase planners use in regards to resolving congestion issues: "You can't build your way out of congestion." The concept to which this phrase refers is induced demand. The idea is that when building new or expanding old highways in order to alleviate congestion, you create the unintended consequence of encouraging more highway usage than there would have been otherwise. Part of this effect is triple convergence. When a new highway opens, people change their (1) route, (2) timing, or (3) mode of travel if the new highway is more convenient for them. Therefore, almost immediately, the new highway returns to a congested state. For a more detailed description of this process and more depressing news about the invalidity of the majority of congestion 'solutions', check out Anthony Downs' book, Still Stuck in Traffic.
From a systems perspective, we could describe this as the interaction of two self-reinforcing loops, one constantly reinforcing the idea that building more highways is the solution to congestion, the other accruing profits in the industries that are most benefited by highway building (led by land developers). As substantial profits accrue in those industries they are able to both lobby governments and enact public relations campaigns to further enable the constant highway building paradigm. As more highways get built, there are increasingly more people who rely on them for basic transportation needs, which, combined with the aforementioned PR campaigns, further builds support for highway expansion projects. The increased public support and lobbying efforts lead to more highways being built, which means more of the those effects that created the problems in the first place. This is the nature of a self-reinforcing loop.
I cannot claim to be an expert in systems theory, but I do think that it's very important to understand urban systems before pretending to know the proper solution to the problems that cities face. I would be interested in whatever suggestions readers might have for future readings in systems thinking that might expand my understanding. I also hope that practicing planners begin to incorporate systems thinking into their understanding and decision making. The public too, should be encouraged to use systems thinking when evaluating proposed plans and engaging in civic life. Failing to look at problems from a systems perspective may lead to unintended consequences that overshadow the original issue. It is important to ensure that the cure is not worse than the disease.
 |
| Dynamic Stock and flow diagram of Adoption model(small version).
Diagram created by contributor, with software TRUE (Temporal Reasoning Universal Elaboration) True-World Model from article by John Sterman (2001) Systems dynamics modeling: tools for learning in a complex world, California management review, Vol 43 no 1, Summer 2001}} |
Cities are systems. Much as we now recognize that the biological world is full of interconnected systems called the ecosystem, we should now also realize that there is a mirror of that world in the city. Urban systems are composed of people and organizations of people. Towns and cities are made of both constituent parts: businesses, churches, schools, political organizations, social groups, etc. as well as the interconnected stocks and flows that make for complex systems. All of these parts interact and create communities that themselves overlap and interact to form neighborhoods, towns and cities. Understanding cities as systems helps us to understand the reverberant consequences of our actions in urban planning.
Having a particular interest in transportation issues, I wanted to look at a popular example describing, in brief detail, how a systems perspective might help us understand the dynamics at work. The example being the popular phrase planners use in regards to resolving congestion issues: "You can't build your way out of congestion." The concept to which this phrase refers is induced demand. The idea is that when building new or expanding old highways in order to alleviate congestion, you create the unintended consequence of encouraging more highway usage than there would have been otherwise. Part of this effect is triple convergence. When a new highway opens, people change their (1) route, (2) timing, or (3) mode of travel if the new highway is more convenient for them. Therefore, almost immediately, the new highway returns to a congested state. For a more detailed description of this process and more depressing news about the invalidity of the majority of congestion 'solutions', check out Anthony Downs' book, Still Stuck in Traffic.
From a systems perspective, we could describe this as the interaction of two self-reinforcing loops, one constantly reinforcing the idea that building more highways is the solution to congestion, the other accruing profits in the industries that are most benefited by highway building (led by land developers). As substantial profits accrue in those industries they are able to both lobby governments and enact public relations campaigns to further enable the constant highway building paradigm. As more highways get built, there are increasingly more people who rely on them for basic transportation needs, which, combined with the aforementioned PR campaigns, further builds support for highway expansion projects. The increased public support and lobbying efforts lead to more highways being built, which means more of the those effects that created the problems in the first place. This is the nature of a self-reinforcing loop.
I cannot claim to be an expert in systems theory, but I do think that it's very important to understand urban systems before pretending to know the proper solution to the problems that cities face. I would be interested in whatever suggestions readers might have for future readings in systems thinking that might expand my understanding. I also hope that practicing planners begin to incorporate systems thinking into their understanding and decision making. The public too, should be encouraged to use systems thinking when evaluating proposed plans and engaging in civic life. Failing to look at problems from a systems perspective may lead to unintended consequences that overshadow the original issue. It is important to ensure that the cure is not worse than the disease.
No comments:
Post a Comment