The compact city or city of short distances is an urban planning and urban design concept, which promotes relatively high residential density with mixed land uses. It is based on an efficient public transport system and has an urban layout which – according to its advocates – encourages walking and cycling, low energy consumption and reduced pollution. A large resident population provides opportunities for social interaction as well as a feeling of safety in numbers and "eyes on the street".The Death and Life of Great American Cities (1961) New York: Random House. It is also arguably a more sustainable urban settlement type than urban sprawl because it is less dependent on the car, requiring less (and cheaper per capita) infrastructure provision (Williams 2000, cited in Dempsey 2010).
Achieving a compact city does not just mean increasing urban density per se or across all parts of the city. It means good planning to achieve an overall more compact urban form: The compact city model, ideally, creates benefits that are attractive to modern urbanites. The desired benefits include shorter commute times, reduced environmental impact of the community, and reduced consumption of fossil fuels and energy. However, research on compact cities from around the globe suggests that these outcomes are not guaranteed. To make matters worse, the design of the cities is limiting residents' access to green space and reasonable views. For the compact city model to gain in popularity, it is necessary to review both their pros and cons.
Origins The term compact city was first coined in 1973 by George Dantzig and Thomas L. Saaty,Dantzig, G. B. and Saaty, T. L., 1973, Compact City: Plan for a Liveable Urban Environment, W. H. Freeman, San Francisco. two mathematicians whose utopian vision was largely driven by a desire to see more efficient use of resources. The concept, as it has influenced urban planning, is often attributed to Jane Jacobs and her book The Death and Life of Great American Cities (1961), a critique of modernist planning policies claimed by Jacobs to be destroying many existing inner-city communities.
Among other criticisms of the conventional planning and transport planning of the time, Jacobs' work attacked the tendency, inherited from the garden city movement, towards reducing the density of dwellings in urban areas. Four conditions were necessary to enable the diversity essential for urban renewal: mixed uses, small walkable blocks, mingling of building ages and types, and "a sufficiently dense concentration of people". The 'sufficient' density would vary according to local circumstances but, in general, a hundred dwellings per acre (247 per hectare – high by American standards, but quite common in European and Asian cities) could be considered a minimum.
Important terms
To understand a discussion about compact cities several key terms need to be defined. The first term is urban density. Urban density refers to how many people live in a square mile of land. It is used as a variable in evaluating how livable a city design is. The optimal urban density for compact cities is high enough to keep residents close to community amenities but low enough to allow residents access to green spaces, reasonable privacy, and acceptable views.
Another term associated with the discussion about the compact city commuter is self-sustaining. Self-sustaining means that the city has everything that a person needs within the community. This includes stores, employers, a post office, service providers, energy generation, waste disposal and processing, and small-scale agricultural production (community gardens and/or vertical gardening).
Since the objective of the compact city is to make the community as accessible as possible to residents, the term pedestrian design also needs to be defined. Pedestrian design means that the compact city's layout and features support pedestrian traffic. This is an important part of a compact city design because it facilitates the flow of foot and bike traffic through the community. While a pedestrian design will primarily focus on hardscape elements, such as pathways and sidewalks, green space also is important to consider.
Green space, defined as the areas of nature found in the landscaping of a community, includes grassy patches, flowerbeds, trees, rock gardens, and water features. Green space is important in compact city designs because they enhance the aesthetics of the community. It also helps to control storm runoff, and they help to remove CO2 and other toxins from the air.
Proximity is the final term that needs to be defined. It refers to how close a community's amenities are to where people live. Ideally, compact cities will keep key amenities within walking distance of people's homes. The acceptability of proximity to different amenities is calculated based on travel time and distance.
The compact city and related concepts
Although the concept of 'compact city' was coined by American writers, it has been used more in recent years by European and particularly British planners and academics. See, for example, the writings of Michael Jenks.Jenks, M., Burton, E. and Williams, K. (Editors), 1996, The Compact City: A Sustainable Urban Form?, Spon Press; .
In North America the term 'smart growth' has become increasingly common linked to the concept of 'smart city'. The concept of 'smart growth' is very similar to 'compact city', although 'smart growth' carries more strongly normative connotations, implicitly accepting the emphasis in current mainstream debates that growth is necessary and good. The term is often used loosely to accommodate these debates
Cognate concepts include 'sustainable urban development' with no presumption that development equals growth.
Another alternative concept is 'green urbanism'. Steffen Lehmann has extensively written about the compact city and green urbanism. His work presents a series of international case studies and outlines 15 core principles for the design of compact, sustainable cities.
The compact city and proximity Compact cities are intended to provide all one needs to live in one community, including work opportunities. Someone who works in a compact city can walk or bike a short distance to work instead of driving. This reduces fossil fuel consumption and emissions and pollutants, as well as traffic density. This is a main selling point of a compact city. However, not everyone finds work in the city, and consequently many people commute to neighboring cities for work. This has two drawbacks: commuting time and the impact of commuting.
A study by Boussauw et al. found that commute times depend on urban density and the diversity of structures found in the community. The findings show that shorter commutes correlate with high values for density, diversity, and job accessibility. Thus proximity to work within a compact city needs the city to include structures that are appropriate for businesses in different industries; it also depends on the city's density of development. The more developed the city is, therefore, the more employers can be located there, and the fewer employees will need to commute long distances.
Proximity also affects residents' access to green spaces. This is related because the more green space a community has the lower the development's urban density, thus increasing average commuting distance. In a study by Wolsink, participants viewed community proximity to green spaces as important, because green spaces provided recreational and educational opportunities, enhanced mental health, made the city more attractive. These benefits made additional time in commutes acceptable to residents. However, to remain acceptable, the proximity range needed to remain reasonable.
Compact cities and sustainability Another selling point of compact cities is that they are supposed to be sustainable developments. However, recent studies suggest that these developments are not as green as promised. For example, in the study by Rérat, the author discussed three criticisms of the compact city model. The first criticism was that supply and demand alignments are not feasible in some cases. What this means is that there are limits to how many people can fit into a space because of resource and design limitations. Additionally, while a high-density may be achievable, it likely will counter the demands and expectations of residents who want more privacy and more personal space. The second criticism of the compact city is that to produce highly desirable living conditions and a high quality of life, the cost of living needs to increase. Consequently, integrating desirable traits into compact cities makes the living spaces expensive, pricing out lower-income families and pushing them to the outskirts of town. This stimulates urban sprawl and places the burden of longer commutes on low-income workers, further expanding disparities in wealth and quality of life. The third criticism of the compact city is that its environmental impacts are significant. Dense populations mean waste and pollution are also dense. This concentrates the impact of communities and necessitates expensive control mechanism.
Rérat is not the only researcher showing evidence that compact cities are not as sustainable as promised. The work by Westernick et al. also show that there are sustainability trade-offs found within compact city designs. Westernick et al. compared compact cities to dispersed cities to see where sustainability factors differed. The findings showed that compact cities excelled in efficient land consumption, more flexible land use patterns, cost efficiency of development and maintenance, and reduced reliance on fossil fuels and motor vehicles. In contrast, however, the sustainability disadvantages included higher vulnerability to disaster impacts, less personal space, less green space where people live, and higher environmental impact because of density. These drawbacks make compact cities less sustainable and justify the need for design improvements.
The compact city, urban sprawl and automobile dependency
Whether the compact city (or 'smart growth') does or can reduce problems of automobile dependency associated with urban sprawl has been fiercely contested over several decades. An influential study in 1989 by Peter Newman and Jeff Kenworthy compared 32 cities across North America, Australia, Europe and Asia.Cities and Automobile Dependence: An International Sourcebook, Newman P and Kenworthy J, Gower, Aldershot, 1989. The study's methodology has been criticised but the main finding that denser cities, particularly in Asia, have lower car use than sprawling cities, particularly in North America, has been largely accepted – although the relationship is clearer at the extremes across continents than it is within countries where conditions are more similar.