Urban sprawl is defined as the uncoordinated growth of a community, usually away from an urban centre into outlying areas. This is usually without concern or consequence to environment or societal impact. Interestingly, it is not always due to population density, but a mixture of socio-economic factors. Such as means of transportation, price of land, house prices, cultural constraints, preference for rural living, demographic trends, pollution, and changes in city culture. It is one of the most studied phenomena of the last ten years due to rapid rate of expansion and the severe consequences it could have on city dwellers, environment, and infrastructure.
Transport and Distance
Transportation is one of the most important infrastructure elements for cities. It is the connector of people to resources, opportunities, and social interactions. The transport modes we are referencing are bus, car, trains, and taxis. We are excluding active transport from this section, which is the ability to walk, run or cycle to a destination. Currently, as cities expand the more commuting time increases. However, it does not have to be this way, plenty of studies have shown that density and mix use development helps reduce commuting times as it reduces the distance between places.
In this section we will look at the consequences of distance and transport modes on human cognition and physiology.
The Unintended Human Consequences
This section will focus on four consequences of transport; poverty, social exclusion, stress, and toxicity. All of these areas have cognitive and physiological consequences.
A recent report produced by UCL, discusses how poor access to transport contributes to poverty and social exclusion. These two factors separately and together have correlates to longer term cognitive and physiological consequences such as obesity, depression, and anxiety. Furthermore there are also links between obesity, depression, and anxiety, often found as comorbidities of each other. In other words people with obesity may also to also be anxious or depressed and visa versa. This is important as it shows the high human cost and significance of the issue.
Stress can be caused by an array of environmental elements or stimuli, long commutes in both automobile and trains are well documented and researched environmental stressors. More research needs to be done to understand the long term cognitive effects of transport, specifically in the context of productivity. For example, do stressful commutes affect our ability to focus at work? Or do they have an effect on brain systems such as memory and attention? Two systems that are linked to learning new skills and information.
We should also consider the elderly and those with physical variances as they have statistically less opportunity to access transportation due to having personal mobility challenges. Improving access to transport for these groups will have an impact on their feelings of isolation and social exclusion. Which have links to anxiety and depression. Additionally in the case of the elderly there is a correlation between feelings of loneliness and cognitive decline.
The final consideration is the exposure to toxins in public transport systems as they may have long term has long term effects on our mental and physical health. A Canadian study looked at the level of daily exposure to PM2.5 in the underground metro network of three major cities. It identified that a typical 70 min commute, which constitutes 4.9% of the day, was estimated to contribute to over 50% of the estimated daily exposure to several PM2.5 metals. In turn this has an effect on rates of asthma, developing respiratory inflammation, and lung function. Furthermore, there is now evidence that long term exposure of PM2.5 can influence the onset of severe depression, with symptomatology so acute, it is leading some people to request the help of emergency services15.
The problem is not cities growing, the problem is how they grow. With the right infrastructure we can mitigate many of the challenges mentioned in this section
Relevance to Built Environment
One of the challenges in creating solutions within cities is knowing where to start or what solution will have the most impact. With neuroscience pointing out the infrastructure elements that have the most acute biological consequences, industry can use this data to create guidelines, which can aide with decision making on mix use developments or in understanding what planning initiatives to prioritise.
Those living on city peripheries can feel excluded and find it hard to take up available jobs unless there is transportation linking them to the centre. The Brazilian city of São Paulo is experiencing commutes of up to 4 hours where almost 70% of journeys are made by bus. In some municipalities like Itaquaquecetuba in the extreme east of the city, bus transportation is the only link to work. This translates to forcing poor people to endure, not only the mental stress of extremely long commutes, but also long exposure times to pollutants as they sit in traffic, which can have severe mental and physical health implications.
There is also a nutritional factor, that many ghettoised places outside of city centres have higher incidences of malnutrition due to poverty and lack of access to fresh food. Malnutrition is not only a physical experience, it also has vast neurodevelopment problems, which can lead to lifelong disorders, such as schizophrenia and antisocial personality disorders. Therefore urban planning concepts like density where there are various options to access food and work can help mitigate against long term debilitating mental disorders.
How to transport people from A to B is a long studied concept and the role of neuroscience is from two perspectives. The first is research to support the longer term biological effects to validate city planning strategies. The other is way finding, especially in public transport. Part of the access problem with the elderly and the physically variant is that it is not intelligible to them. For example, someone with visual impairment may find it difficult to navigate complex tunnels and multiple access points, which can act as deterrent, decreasing their desire to access their local transport link. In the case of the elderly, legible and clear signposting, auditory instructions, and better safety measures would increase use as it would make transport less confusing and daunting.