Can you address the traditional role of density in the design of urban environments and how you envision future development?
Teemu Jama: Since rapid urbanization began in the early years of the 20th century, the volume of real estate development has been the key interest of planners. A variety of zoning rules used by local planners over time has come to reflect a particular zeitgeist. While most rules become passé, density has managed to endure. It has been a simple way to track the performance of plans. Density has also been linked to social interaction, creative economies and environmental sustainability in many urban studies.
I argue that today in the 21st century the urban world has seized the benefits of agglomeration characteristic of cities, while the new mobile economy is disrupting many industries; therefore, it is time to question the need for physical proximity. Density no longer offers the pervasive relevance it once did in urban development. As more people move to cities, urban environments do become more dense, but enabling local growth and fostering livability requires broadening the metrics standardly applied.
Risto Jounila: Traditionally, transport planning starts with numbers based on gross floor area [GFA], which gives us the density in a defined area. This density forms the basis for the number of residents and jobs in a given area. These numbers from various GFAs, created by urban planners, are fed into a transport model, which guides the design of the transport network in urban environments.
The transport model calculates projections of transport demand for different transport modes according to the region-specific urban transport modelling data practice. The urban transport modelling guidelines are based on current existing urban forms in that geographical area. This process has led to car-dependent urban environments, notably in western countries.
The traditional purpose of transport planners is to apply the projected traffic flows coming from the transport model. In other words, transport planners do not aim to manage transport demand. Teemu and I have noted that there is a need to think differently and take a more comprehensive approach, challenging the current transport paradigm which is based mainly on density.
How can a more comprehensive approach shape livable cities?
Teemu Jama: We need to unlearn density-based planning and start by focusing on other features of urban environments. Density, the building volume within a predefined area, has been the main metric in urban planning for a long time, so it is not easy to let it go. Urban modelling paradigms, from BIM [building information modelling] to CIM [city information modelling], also rely heavily on volume calculations. In addition, AI [artificial intelligence] technology in most smart city solutions does the same. Therefore, the criteria used in models to drive urban plans should be reconsidered and carefully selected. For example, relative to AI, the internet of things and automated vehicles have very different requirements compared to humans.
It is time to identify new factors that are vital to support the needs of citizens, the health of the environment and our planet. One option is to replace the concept of density with the concept of diversity in planning projects—diversity as it applies to land use, the people who live and work in urban areas, and the environment, so biodiversity. This change will lead to a very different type of paradigm.
Urban planners and traffic engineers need to rethink together how to arrive at sustainable solutions. Joint examination enables proper consideration of the elements that shape sustainable solutions. Implementing these solutions requires a transformation of processes, from the funding criteria of infrastructure projects to the calculations of ROI [return on investment] for real estate investments.
Risto Jounila: Creating diverse places in cities also requires a step change within the planning process itself. As I mentioned earlier, transport planners currently focus on accommodating the transport demand that is generated from a transport model. They have not historically applied the diversity of urban form to guide these transport patterns to be more sustainable.
Transport planners do not normally try to minimize transport demand, as in the number or length of trips that people will take. If there is a diverse area, destinations and origins will be closer together. People can combine trips instead of doing multiple trips to take care of their needs. Also in diverse areas, trips are likely to be shorter than in areas where urban form is homogeneous. Transport demand can be minimized within cities and supported accordingly when the right kind of diversity informs urban form. In turn, this reduction in travel will also support decarbonization efforts in transportation.
To effect change, the planning process should be led by common goals for all professionals involved. Moving away from current practice, which is deeply rooted in achieving density, requires breaking down the silos that professionals across the transport sector and in land-use are used to working within so that, as Teemu said, professionals can rethink together.