In February 2021, the Netherlands Environmental Assessment Agency published a blog post titled “A choice for 2050: The Netherlands more compact, more polycentric, or more diffuse?”. The post discussed three scenarios of urban development in the country, based on the ESPON project Sustainable Urbanization and Land Use Practices in European Regions (SUPER). The scenarios were: compact, polycentric, and diffuse, with each scenario having different implications for land use, sustainability, and quality of life.
The post raised a fundamental question: how should urban areas grow and accommodate the increasing demand for housing and services? This question is not unique to the Netherlands. Many cities worldwide face similar challenges in balancing the needs of people and the environment. One of the possible solutions is infill development, which refers to the reuse of vacant or underutilized land within existing urban areas. Infill development can reduce urban sprawl, increase density, and revitalize neighbourhoods.
However, infill development is not without obstacles and trade-offs. It may also entail higher costs, social conflicts, and design constraints. Moreover, infill development may not always reflect what people want. For example, some may prefer low-density living in greenfield areas, while others may value proximity to urban amenities and services. So, how can planners and policymakers reconcile these preferences with the goals of sustainability and efficiency?
The history of infill development versus city expansion can be traced back to the origins of urbanization itself. Throughout history, cities have grown and changed in response to factors such as population growth, economic development, technological innovation, social movements, and environmental challenges. Different urban forms
have emerged due to these factors, such as compact, sprawling, polycentric, and vertical cities.
In general, urban development can be classified into two types: extensive and intensive. Extensive development refers to the horizontal spread of urban areas, often at the expense of natural or agricultural land. Intensive development refers to the increase of density and diversity within urban areas, often through infill development or vertical layering.
The choice between extensive and intensive development has varied across time and space, depending on the historical context and the preferences of urban actors. For example, in the 19th century, many European and American cities experienced rapid industrialization and urbanization, which led to overcrowding, pollution, and social problems in the inner city. As a result, many people moved to the suburbs or the countryside, seeking more space, comfort, and health. This trend was facilitated by the development of transportation and communication technologies, such as railways, automobiles, and telephones. Urban sprawl has become a dominant form of urban development in many parts of the world.
In recent years, infill development has become more popular and desirable as a way to deal with the problems of urban sprawl and promote smart growth. Infill development has different pros and cons depending on how it affects the environment, the economy, the society, and the space. Infill development can also be compared with city expansion to see the trade-offs and synergies between them.
For the Netherlands, the three scenarios of urban development for 2050 from the Netherlands Environmental Assessment Agency are: compact, polycentric, and diffuse. Each scenario has different impacts and trade-offs on land use, accessibility, liveability, environment, and economy. Compact development ranks well for most indicators, except for urban green spaces and housing demand. Polycentric development is good for most indicators overall. Diffuse development is the worst for most indicators, except for affordable housing and housing demand. Therefore, the choice of the urban form should be based on careful consideration of the advantages and disadvantages of each scenario.
However, in the second half of the 20th century, urban sprawl also faced increasing criticism for its negative impacts on the environment, the economy, and society. Some of these impacts include loss of biodiversity, soil erosion, water pollution, greenhouse gas emissions, traffic congestion, infrastructure costs, social segregation, and loss of cultural heritage. In response to these challenges, many urban planners and policymakers advocated for more compact and sustainable forms of urban development, such as infill development. Infill development was seen as a way to revitalize existing urban areas, make use of underutilized land and buildings, reduce infrastructure costs, enhance accessibility and mobility, promote social diversity and cohesion, and preserve natural and historical resources.
Yet, infill development also faces some obstacles and trade-offs. Some of these include higher land prices, regulatory barriers, community opposition, design constraints, displacement of existing residents or businesses, loss of open space or privacy, and increased noise or pollution. Moreover, infill development may not always align with the desires of residents. Some people may prefer low-density living in greenfield areas for various reasons, such as affordability, lifestyle preferences, cultural values, or personal aspirations.
Therefore, the history of infill development versus city expansion is not a simple story of one replacing the other. Rather, it is a complex story of how different urban forms have coexisted and competed with each other over time and space. The choice between infill development and city expansion is not only a technical or economic one but also a political and social one. It reflects different visions of what a city should be and how it should grow.
Another example is Los Angeles County, California, where infill developments positively impact local housing prices. The impact starts before the start of the new project. New developments built on teardown sites have a more substantial effect than those made on vacant or underutilized areas. The pricing of units in the new development also affects the impact. Infill development could increase the value of existing neighbourhoods and generate positive benefits for local residents. Furthermore, infill development is here an effective way to solve the local housing shortage.
In conclusion, the choice between infill development and city expansion is complex, reflecting different visions of what a city should be and how it should grow. While infill development can reduce urban sprawl, increase density, and revitalize neighbourhoods, it may also entail higher costs, social conflicts, and design constraints. Moreover, infill development may not always reflect what people want. Some may prefer low-density living in greenfield areas, while others may value proximity to urban amenities and services. On the other hand, city expansion can provide more space, comfort, and health for some people but also negatively impact the environment, economy, and society. The choice between these two options should be based on careful consideration of the advantages and disadvantages of each scenario.
As we move forward into the future, we must ask ourselves: what kind of cities do we want to live in? Do we want cities that are compact and sustainable or sprawling and inefficient? Do we want cities that prioritize people or cars? Do we want cities that are diverse and inclusive or segregated and exclusive? These are not just technical or economic questions but also political and social ones. They reflect our values, our aspirations, and our vision of the good life. The choice is ours to make.