Making sense of cities

Why do we need to understand cities? The UN records that more than half the world’s population currently live in cities, and that this is likely to increase to two thirds by 2050 .??

The really important part is that the environment we live in affects what we can do every day, which in turn has longer-term impacts. For example, more people walking or cycling to work means more active people, which has health and well-being benefits. It also means; fewer cars on the road, less congestion, less pollution, reduced fossil fuel use and local economic impacts etc . If we can get more people walking and cycling, we can start to address some of the big challenges of the 21st century including climate change, health and well-being.?

?But these types of outcome are the result of complex interactions between multiple systems, across multiple scales, at the same time. These interactions combine the decisions of individuals within a wider socio-economic, demographic and cultural context. Importantly, some factors are more significant than others, with the decisions and behaviours of individuals taking place within a physical environment which makes some activities easier than others . As Architects, Planners and Urban Designers, we need to understand the effect of the elements we have some influence over.??

Although buildings might be re-placed or re-built as often as every 25 years, the wider built environment changes very slowly. Once the big systems, especially street networks and land ownership are defined, we’re locked-in to it for at least a generation, and probably a lot longer.?

?To understand the influence of the built environment, we can represent it using models, then analyse cities from the point of view of a person (a follow up post will explain this in more detail). Models are important because they can give a consistent description of how the combination of streets, land use and public transport systems work together. This description can help explain how the built environment influences daily activities such as active commuting, and is in turn linked to health and well-being outcomes . And this is important, because if we don’t know how the design of the built environment contributes to an outcome, we don’t know if, or how we should change the environment to improve these outcomes.?

?By analysing whether consistent conditions are associated with particular activities it is possible to see the combined influence of the built environment systems, for example; the mode people use to travel to work can be compared to the way that street networks, urban block sizes and land use distributions combine to affect the number of jobs within 15 minutes’ walk of every house.??

We can learn from places that do and don’t work well, and also from the outliers (for example places where socio-economic indicators might suggest a different outcome). There are causation and correlation arguments to consider; there will always be other factors influencing daily decisions and complex long-term outcomes, and while it might not be possible to guarantee a positive outcome based only on the design of the built environment, at least we can make a positive outcome possible (unfortunately, this is something that doesn’t always happen and there are many cases where fragmented street networks, low densities and areas of single use create car dependent environments where only the most determined people can walk to work).?

Using this knowledge, we can then design new places that enable active lifestyles, identify areas with underlying conditions that support intensification, or see areas of risk that need to be addressed or mitigated. In my next post I’ll explain how Integrated Urban Modelling can do this.?