Ending sprawl: A blueprint for building sustainable cities

PATRIZIA: Peter, your latest work, produced with the World Bank, is Ending Sprawl: Urban Design Standards for a Resilient and Sustainable Future. Why do you emphasise ending sprawl (spreading of urban developments near to cities) as essential to a sustainable future?

The second is low-income sprawl, evident in cities like Mexico City, São Paulo in Brazil, Lagos in Nigeria, and Nairobi in Kenya. In rapidly growing poor cities, sprawl occurs as the urban poor settle on the peripheries. This results in long commutes, poor access to services and a lack of infrastructure, making daily life challenging.

Finally, there is high-income sprawl, found in much of the Western world, particularly the United States. This involves low-density subdivisions, office parks and shopping malls that segregate communities by income, family type and age. It leads to isolated neighbourhoods dependent on cars. Despite the differences, the three types share common urban pathologies: isolation, poverty, water, air and land pollution, congestion, loss of community, degraded health and economic headwinds. The solutions also share commonalities. 

PATRIZIA: And they are?

Peter: There are four principles: diversity, walkability, preservation and conservation, and connectivity. First, we must create human-scale, walkable environments with interconnected blocks and mixed-use developments that encourage a diverse population and reduce car dependence. Protecting natural resources and green spaces while restoring degraded urban areas is also essential, as is connectivity. Cities need well-connected transportation networks that integrate various modes of travel to make them more accessible and reduce congestion.

PATRIZIA: Cities in the Global South are poor and are being overwhelmed by urban growth. Would this really work there?

Peter: In such cities, integrating essential infrastructure and services in new developments is crucial. Step one is creating places where the poor can settle and build own homes. The next step is providing basic services in these areas, such as a network of streets for accessibility. It's also crucial to offer land security so residents can build equity in their homes. This approach, known as ‘sites and services’, involves the public sector in ensuring clean water, sanitation and electricity. It’s a stripped-down approach compared to subsidised housing, but subsidised housing is often limited in how much can be provided, so enabling people to build their homes in well-planned areas is more sustainable.

We also need a regional plan to guide where developments should occur, ensuring they are strategically placed and well-supported by infrastructure. Regional planning can help integrate essential services, transportation networks and land use policies. This ensures that development is not just about building houses but creating communities.

PATRIZIA: What are some recent projects where you have applied these principles?

Peter: The Denver Stapleton project is transforming a decommissioned airport into a mixed-income, mixed-use community featuring diverse housing options from high-end homes to subsidised, affordable cottages. This walkable, bikeable area includes main street shopping and an extensive open space network. It is recognised as one of the largest and most successful infill projects in the US and, upon completion, will have converted 7.5 square miles of runways and terminals into a community for 30,000 residents, created 13,000 jobs and provided 1,100 acres of new parks and open space.

I also have great hopes for the Grand Boulevard concept, developed with UrbanFootprint. It involves converting undervalued and underutilised strip commercial to mixed-use, mixed-income workforce housing. For example, the underutilised land lining the Inner Bay Area’s 700 miles of arterials totals 15,400 acres.

This could provide up to 1.3 million new houses with 260,000 affordable units close to jobs and existing services. This infill housing strategy would upgrade dying strips without disrupting stable neighbourhoods or displacing existing housing.

At the same time, existing road spaces can be converted from auto-only asphalt nightmares into liveable, multi-modal boulevards with new transit, bikeways, trees and generous sidewalks. This strategy, supported by California’s recently passed AB 2011 that will streamline the approval process for affordable housing developments, can help solve the housing crisis.

PATRIZIA: How critical is it that cities end sprawl?

Peter: It's absolutely critical. I often say our problems are ‘cars and cows’. Our heavy reliance on cars leads to substantial carbon emissions, which are a significant driver of climate change. On top of that, the large-scale agriculture needed to support meat consumption, especially cattle, results in deforestation and habitat destruction, causing further environmental damage.

PATRIZIA: What role does artificial intelligence (AI) play in creating cities of the future?

Peter: AI has the potential to revolutionise urban design. It can enhance our capacity for planning and representation, but it’s inherently backwards-looking, relying on past data. Innovation in urban design requires forward-thinking and visionary planning.

For example, AI can assist in developing renderings and simulations, providing detailed visualisations of proposed projects. In our work, AI helps us represent urban environments beautifully, although it cannot yet design a community that people would want to live in without human guidance. AI should always be directed by innovative scenario planning and human creativity to reshape our cities for the better.

This article is extra content created for the digital version of our thought leadership magazine, estatements. Take a look at the magazine here: Welcome - estatements magazine Edition 2, 2024