Urban Form and Sustainability: the Planner’s Toolbox

By Ryan Weber, Lars Berglund & Christian Fredricsson

Planners and policymakers face the difficult task of working in a complex, interconnected and ever-changing world. They face challenging decisions regarding the design of policies for sustainable development, because the integrated management of different types of land use involves systems in which natural and human factors are closely interconnected. This includes the struggle to balance the demands of growth with the desire to preserve the natural environment and other quality-of-life attributes - all while ensuring that the interests of many actors are acknowledged and accommodated.

In a Nordic context, the physical planning domain is endowed with a significant degree of control over development of the urban form, because a strong tradition of comprehensive planning is evident. As a result, the overall aim of successful land-use planning should be for land to be used for the purpose to which it is best suited, and policies should be designed to minimise possible negative externalities and impacts on the environment and society. The result is that physical planning can exert significant control over land change processes through restrictions on development in some areas and stimulating development in others. This is often in contrast to planning in North America, where market-driven processes tend to prevail.

Discussions concerning the norms of urban planning that act as a back-drop for physical planners continue alongside the evolution of social, economic and spatial patterns. An important aspect of these discussions over the past 25 years concerns the inefficiency of low-density urban sprawl and the resource efficiency of proposed solutions, including strategic densification and compact city development. The discussion includes the expanding number and quality of tools that are available for urban planners to reconcile urban development with environmental objectives. This topic has been an important focus of Nordregio's and WSP's joint work within the Nordic working group on green growth – sustainable urban regions, where specific emphasis has been placed on the use of integrated land-use models.

Many types of tools and methods are available to assist planners and policymakers in a variety of ways. Some, such as impact assessments, are legally mandated. Others, such as life cycle analyses, certification schemes, eco-labelling or GIS mapping and monitoring, are voluntary. In one way or another, these are used to structure the work of planners. They provide clearer statements of existing problems and possible solutions, legitimise sustainability efforts, motivate investment, document plans and achievements and include new participants in decision-making processes. As the author of the next article eloquently stated a number of years ago, planning tools are based on the view that what gets measured and monitored gets managed, therefore increasing the likelihood of strategic goals being achieved.

Urban form and sustainability

More than any other issue, improving the environmental sustainability and attractiveness of our cities comes down to how and where to build buildings. In terms of 'how', the buildings constructed thus far require far too much energy to sustain our activities. While we did not have nearly the same level of knowledge of the environmental impacts of fossil fuel consumption 40 years ago, the fact remains that Europeans consume more than 40% of their total energy demand in buildings, which is approximately 13.4 billion barrels of oil per year.

In terms of the 'where', however, buildings continue to be built in the wrong places – in locations that create too much importance for the private car as the dominant form of transport. Contemporary urban sprawl is the result of a market-driven process, proliferated by cheap energy and the rapid growth of private cars as a symbol of wealth and an affordable means of transport during the first half of the 20th century. Urban planning and design adjusted quickly to the demand for car infrastructure required by suburban living and unrestrained land acquisition from agricultural areas, forests and other open spaces that became the norm as extensive road networks were constructed. The availability of the car meant that land-use functions could be separated by single-use zoning, precipitating even lower residential and job densities and making the private car the only rational means of transportation.

Two alternatives to urban sprawl are the interrelated concepts of strategic densification and compact city development, which foster a more sustainable urban form through relatively high residential density and mixed land uses. In a perfect world, this would produce urban spaces that were much more resource efficient because walking, cycling and public transport would be the most attractive options for moving about in everyday life – between home, work and school, and for recreation and shopping. To give an appreciation of the real-world connection between urban form and transport, the table below shows a clear correlation between the density of residential buildings and the attractiveness of non-car forms of transport. While the private car is necessary for almost 70% of daily trips in a low-density residential setting, this is reduced to just over 20% for typical inner-city residential blocks.

Modal split and building density

Click to view larger image

Integrated approaches to planning

Assessment of a plan's impact has historically often been an intuitive process, based on planners' experience and qualitative considerations. Very often, it has been difficult to quantify the impact of various planning strategies and policies in terms of land use, accessibility and environmental impacts in a coherent manner. In addition, planning specialists (e.g. transport planners and land-use planners) have typically designed different parts of the plan and assessed the possible impacts separately within their own fields, resulting in a lack of true integration between planning fields. Historically, this can partly be explained by a lack of appropriate planning tools.

The importance of integrating land use and mobility issues is reflected by the City of Vancouver's former Planning Director Brent Toderian who rightly states: "The best transportation plan is a great land use plan." Taken a step further, the latest book from Michael Batty, who contributed to the third article in this issue, opens by discussing how we still, too often, think of cities singularly in terms of places and spaces that are stitched together by transportation. This is in contrast to the opinions of a wide-ranging group of important urban thinkers – such as Jane Jacobs, Peter Hall Manual Castells and others – who in their own ways describe how cities are most importantly defined and planned based on the relationships, networks and flows from which locations emerge.

Even when the public recognises the importance of integrating the transport and building dimensions of urban planning, planners must still consider many land-use issues to achieve good city building, particularly in expanding cities where competition for land is intense. This includes factors such as environmental risks, protected green spaces, land values, in addition to social issues such as accessibility and segregation. It is readily apparent that planners face an enormous number of factors, domains and issues that interact with and feed back to one another in very complex ways.

To capture and address this complexity, planners use tools that include integrated urban models, for which there are a number of terms, such as land-use models and land-use transport interaction models. These models provide simplified representations of the real world, and can be used for studying the impact of various spatial planning policies in a systematic way. A typical integrated urban model allocates predicted numbers of houses and work-places spatially according to a specific planning policy, thereby creating a new urban landscape. Because one very important consequence of a new urban configuration is the change that can be expected in terms in travel behaviour, these urban models consider transport issues either by considering them in conjunction with a transport model or by integrating the two themes into a single model. The consequences of the future allocations can then be quantified in a number of ways (e.g. future land consumption, loss of green spaces, or identification of land-use conflict areas).

An integrated modelling system provides a number of parallel benefits to planners when they formulate strategic policy decisions. Apart from their explanatory role in understanding the dynamics of urban systems, they have a predictive role by enabling virtual experimentation of various development scenarios. This allows planners to visualise and measure the future impacts of different spatial planning strategies to determine which ones lead to the achievement of planning goals. Additionally, they can be used to stimulate thinking and to facilitate discussion, which means they are powerful tools to facilitate participatory processes of collaborative decision-making.

Thus, even though integrated urban models are NOT intended to provide definite or predictive statements about the future, they can be a very powerful tool-box to quantify several aspects of the complex urban system coherently and systematically, and to facilitate the design and assessment of appropriate plans and policies for green growth. That said, Nordregio's and WSP's joint review of the use of these tools in the Nordic countries shows minimal use of such models despite a strong tradition of comprehensive planning in the Nordic region. Given that these organisations cite a lack of understanding of the availability and benefits of integrated models as the main reason for not using them, it is clear that more convincing information on the use and benefits of such models is required. This is particularly true for those integrated models that are easy to apply, relatively inexpensive, and proven to provide realistic and insightful outputs that foster deliberation within participatory planning processes.

Back to Nordregio News Issue 1, 2014