Stephen Marshall

The Origins of Complexity Theory in Cities and Planning

We first present a brief history of the origins of the complexity sciences as they have developed with respect to theories and models of cities. Our argument that the original view that cities might be understood and modelled as general systems from the top down, where the focus is on simulating the system in equilibrium, has radically shifted to viewing such systems as being continually out-of-equilibrium with a dynamic driven from the bottom up. This has important implications for how we model cities and we present the key features of a new generation of city models built around these ideas. We set this argument in the much wider context of changes in our perceptions about how we should plan cities. We note that the development of collaborative planning theories that see planning as dialogue between conflicting actors is in turn being influenced by conceptions of complexity. In particular, we argue that this shift from static to dynamic, top–down to bottom–up, is problematic for traditional notions of the optimum city which is inevitably an equilibrium to be aspired to. We conclude with some reflections about the difficulties for prediction that are intrinsic to this view of cities and their planning.

Planning, Design and the Complexity of Cities

Whereas cities are recognised as being quintessentially complex, planning has historically been associated with a reduction in complexity—and not necessarily for the better. The task of city planning becomes how best to generate and maintain the functional complexity possessed by cities. To address this, we need to understand both the complexity of cities, and the ways in which functional complexity could be generated through planning. This chapter first discusses three ways in which urban complexity could be considered beneficial: through perceptual richness, functional capacity and synergy. Then, four kinds of organised complexity are suggested—‘artefactual’ complexity, system complexity, biological complexity and ecological complexity—within which the nature of urban complexity may be articulated. Three consequences of complexity are then discussed: these relate to the unknowability of the system as it is, the unknowability of effects of intervention, and the unknowability of an optimal future state. Finally, the chapter considers how planning could generate functional complexity. It is argued that a system of planning that involves not only design (master-planning) but coding and development control (involving increments of generation and selective feedback) can be recognised as an ‘engine of complexity’, creating something ‘organic’, intricate, iterative, adaptable, and hence functional—but more like evolution than design. It is suggested that recognising the positive benefits of a complex system of planning, capable of generating functional urban complexity, could help avoid mistakes of the past so that ‘planning’ is itself not part of the problem, but part of the solution.

TRAVEL REDUCTION STRATEGIES: INTENTIONS AND OUTCOMES

This paper examines the available types of travel reduction strategies, and evaluates their potential impact by means of case studies. It focuses on travel by car in the 15 European Union (EU) countries, and ways of reducing it. From 1985 to 1994, it is estimated that car travel (passenger km) there has grown by 40%, compared with 6% for bus travel and 3% for rail travel; many factors contribute to these trends. It is important to reduce vehicle travel for environmental, economic, and social reasons. The outcome of travel reduction strategies may be considered in terms of switching modes, destinations, and times of travel, and substitution by linking trips, technology, and trip modification. The level of implementation of these types of travel reduction strategy varies between countries and individual measures within countries. Case studies are presented of: (1) a parking system using telematics and a company bicycle scheme in Aalborg, Denmark; (2) a park-and-ride scheme in Bristol, England; and (3) restriction of city centre car use, extending and improving the cycle network, and raising awareness about car use in Enschede, The Netherlands. They successfully showed possibilities for limited travel reduction, subject to the scope and aims of travel reduction and the assessment of impacts. For the covering abstract, see IRRD 898930.

A strategic assessment of travel trends and travel reduction strategies

Abstract On‐going trends in travel have led to the need to consider the possibilities fir travel reduction, particularly travel by car and at peak times. It has therefore been considered necessary to identify strategies fir reducing the amount of travel to a necessary minimum, considering which components of travel need to be addressed and what types of effects any travel reduction strategies would have on travel behaviour. Accordingly, this paper discusses travel trends in Europe, investigates a set of travel reduction measures and reviews their current implementation. This involves, firstly, the demonstration of significant travel trends, both through statistics at an aggregated level across Europe and findings from a series of individual countries. These trends point to the increase in travel, with increasing number and length of trips, with a particular emphasis on growing car use and dependence. The paper goes on to explore possibilities for applying travel reduction strategies to tackle the observed...

The Potential Contribution of Land Use Policies Towards Sustainable Mobility through Activation of Travel Reduction Mechanisms

This paper explores the ways in which land use planning and the layout of the built environment may assist towards the objectives of sustainable mobility by influencing travel behaviour, in particular towards achieving travel reduction. The paper firstly discusses the different types of land use policy which may be used to assist with the objectives of sustainability and travel reduction, with reference to examples of implementation from Europe and elsewhere. It then places these in a framework distinguishing the nature of land use policies and the mechanisms activated in reducing travel or otherwise promoting sustainable mobility. The paper then goes on to explore in more detail the different mechanisms by which more sustainable travel patterns may be effected through land use considerations, noting how these mechanisms may be combined to amplify the potential scope for travel reduction. Finally, the paper discusses the implications of these explorations for land use policy and hence draws conclusions on the importance of the contribution of land use planning towards sustainable mobility.

The kind of art urban design is

Abstract Advancing the art of urban design invites scrutiny of ‘the kind of art urban design is’. Accordingly, this paper first discusses urban design as art, then uses Fokt’s framework for defining art and Lalo’s classification of arts to suggest fresh interpretations of urban design as an art. The paper then relates urban design to other arts, drawing attention to urban design’s affinity with architecture, landscape architecture, interior and garden design. The paper suggests that urban design can be richer for being an art, without neglecting the possibility for it to be functional or participatory. Advancing urban design as an art implies attention towards suitable means of distilling and instilling collective urban meaning.

Creating More People-Friendly Urban Streets Through 'Link and Place' Street Planning and Design

This article details one method of creating more people friendly streets called “Link and Place” street planning and design in the United Kingdom. Most planners are traffic engineers who are mainly concerned with the needs of vehicles and follow the Buchanan principles, which distinguish between roads meant for traffic distribution and those meant for local access. The article notes several problems with this approach that have all led to difficulties in traveling by foot, bicycle, and public transit. It offers an alternative in “Link and Place” design. This method defines a “Link” as a street for movement by private vehicle, bus, bicycle or pedestrians. A “Place” is a street destination where people spend time primarily on foot. The article then describes a method of classification using a grid, which serves as a means of assessing street performance and a method of street design. An emphasis is placed on including residents in the design, and a case study of this method of design is described.

Creative Challenge and Cognitive Constraint: Students’ Use of A Pattern Language for Complex Design

In A City is Not a Tree, Christopher Alexander identified the creative challenge of how to generate the intricate complexity of traditional urbanism . In doing so, he also hypothesized a cognitive constraint: that it is too difficult for planners to conceive the kind of complexity found in traditional urban structures in a single mental act. To explore the relationship between complex design , creative challenge and cognitive constraint, this chapter reports on student design exercises using Alexander’s Pattern Language as a generator of urban form . The study provides insights into the creative challenge faced by students using patterns in their designs, and helps shed light on the cognitive aspect of design using patterns; and hence draws conclusions about the implications of using patterns for creating complex designs.

Applying evolutionary concepts outside biology

Attempts to apply evolutionary concepts outside biology are not always appreciated by biologists. Recently, Derry has discussed the application of darwinism across a range of fields from cosmology to psycholinguistics [1], and Hansell has critiqued applications of evolution to town planning [2]. Although these discussions point to some difficulties with applying concepts between disciplines—not least the risk of misinterpretation on both sides—we should not underestimate the benefits of transference, in both directions.