Mar 25, 2024
Urban sprawl is the geographical expansion of a city or town, often characterised by low-density housing and an increased reliance on private cars.
This phenomenon is caused by rising urban populations and a desire for space that city outskirts provide. While suburban sprawl can satisfy this desire, the benefit is offset by environmental, social, and economic damage. As such, it’s become a major political issue globally.
In this post, we’ll uncover everything you need to know about urban sprawl. There’s a lot to unpack, so we’ll delve into the causes of urban sprawl, its positive and negative effects, examples from around the world, and practical solutions to reduce its impact.
Urban sprawl is a form of expansion in which low-density housing developments stretch away from an urban centre. It’s also known as suburban sprawl, metropolitan sprawl, and suburbanisation.
The characteristics of urban sprawl — vast land space, big streets and highways, poor public transport systems, and lack of walkable areas — naturally lead to a reliance on personal vehicles. And since most jobs are located in the city or town centre, an influx of residents descend in and out of the city daily, bringing traffic and congestion.
The best metric is by population density — for example, how many people live in 1 square kilometre.
Low-population density areas signal larger, spaced-out housing, while high-population density areas are typically characterised by concentrated housing (apartment complexes and townhouses).
If the overall population density of an area falls, it shows the urban area has sprawled.
United States
Nowhere do urban settlements sprawl as much as in the United States. When it comes to low-density population, America trumps all others.
Urban developments have consistently increased nationwide, even where the population has stagnated. For example, between 1970 and 1990, Chicago’s population grew by less than 5%, but the area’s geographic size nearly doubled.
Today, the lowest-density large cities in the United States are Atlanta, Boston, and St Louis.
Canada and Australia
Outside of the United States, Canada and Australia are other large industrialised countries that show examples of urban sprawl. Since 1999, the total area of urban settlements in Queensland has increased by 11.17%, primarily in Brisbane. In Quebec City, the population increased by 62% between 1971 and 2006, while urbanised areas increased by 261%.
The most textbook urban sprawl example is in Toronto, Ontario. Car-centric developments have engulfed forests and farmland to create 25 municipalities in the Greater Toronto Area.
Europe
In Europe, there are few examples of urban sprawl. Urbanisation within a subset of European countries increased by 20% between 1980 and 2000, which is modest growth compared to other areas.
Most European cities have remained compact and have recently shown signs of densification. European populations have been found to move to the inner city rather than into suburban homes.
Since 2012, European cities have grown steadily in population size while barely growing in terms of their urban footprints.
Elsewhere
In the Middle East, Saudi Arabia’s Ad Dammam has shown astronomical urban development. Its population has doubled 9 times in the past 50 years, and its urban areas have gone from 1,162 hectares in 1964 to 38,670 hectares in 2014.
East Asian and South American cities tend not to sprawl at all.
Suburban sprawl is caused by many factors — the most obvious of which is population increase.
The natural reaction to a rising population is the outward expansion of urban areas. But as we’ve seen in the examples above, the growth of urban areas isn’t restricted to cities experiencing population increase. Sometimes, metropolitan areas with a population decrease have seen just as much suburbanisation.
So, if population increase isn’t the sole driver, what other factors are at play?
Weak planning laws, zoning land for residential use, and lifestyle choices all contribute to urban sprawl.
Because of cheaper land, suburban properties offer more space at attractive prices and greater privacy. So, even if it means being tied to their car, many prefer this option.
Now we’ve uncovered what urban sprawl is and how it’s caused, it’s time to weigh up the negative and positive effects.
Urban sprawl has many negative effects, but the most concerning is a reliance on personal vehicles. And given the vast space, highways, limited public transport routes, and lack of walkable areas, an over-dependency on personal vehicles is inevitable.
With additional private cars flocking to and from city centres, avoidable traffic congestion is created, especially at the start and end of the working day. And with longer and more frequent commutes, there’s an increase in air pollution — something many cities are looking to combat.
Another consequence is the destruction of wildlife habitats, often sacrificed to make way for new housing settlements. Although city planners will always make an effort to preserve as much green space as possible, the remaining space may be too small to support the wildlife that once lived there.
Farming land is also being displaced. The expansion of urban spaces reduces the land available for agricultural production — a problem seen in Ontario, Canada, due to continued urban sprawl.
Given the dependency on private cars, it’s unsurprising there is a correlation between suburban residency and obesity, high blood pressure and chronic diseases (associated with physical inactivity).
With amenities, work, and social events often a drive away, many residents lead sedentary lifestyles and are less likely to walk. These negative health effects of urban sprawl are primarily due to poorly planned communities that don’t encourage physical activity or light vehicles (bikes, e-bikes, scooters).
Residents of newly created suburbs and urban fringe areas tend to have more space than their city centre counterparts.
As developments are built on larger plots, properties are generally more spacious and roomy. Such features can be more appealing to families with young children and pets who need a garden to roam in.
Fringe area properties typically also come with cheaper price tags than comparable residences in the higher-density city limits, making homeownership more attainable for many.
Sprawling cities have become an issue that countries are looking to rectify. But with irreversible developments already in place, rather than shun urban sprawl completely, we must find solutions and implement plans to reduce its negative impacts on the environment, physical health, and social life.
One policy used by city planning officials is urban growth boundaries. These boundaries, which involve mapped lines for designated areas of urban expansion and green/agriculture space, encourage higher-density developments, which counteract the negative effects of urban sprawl.
The most recognised urban growth boundary is in Portland, Oregon, which dates back to the 1970s. Although Portland’s population increased by 50% in the 30 years that followed, new urban developments were concentrated within the boundary, leading to zero urban sprawl.
Experts have recognised the boundary as a reason behind the city’s increased housing density, light vehicle usage (bikes, scooters), air quality, efficient transport systems, and limited rural land disruption.
Other examples of urban growth boundaries include London, Rennes, and new towns in Hong Kong.
The phenomenon of urban sprawl was born in the 1920s amidst the introduction of the automobile. With the personal car making transit possible, populations chose to settle on the outskirts of cities, where there was more space and cheaper housing.
Today, the world’s priorities are changing and it’s time we started to make cities for people, not cars.
To reduce the reliance on private cars, cities must ensure a solid infrastructure for other modes of transport. This includes light vehicles (bikes, e-bikes, scooters), public transit, and shared mobility options like ride-hailing and car-sharing.
To encourage residents to use these transport methods, light vehicles require bike lanes and logistical parking near key transport hubs while ride-hailing and car-sharing need to have free parking available.
For improved public transport usage, services must cover a wide area. People are willing to walk around 500 metres to bus transit, and when transit options fall outside of this range, commuters usually opt for the private car.
Given the breadth of urban sprawl, it’s impossible for public transport to cover every inch of the city, so eco-friendly transport options, such as e-scooters and bikes, near transport links can solve the first-and-last mile problem (the distance from a transit stop to their destination or vice versa).
By removing the number of private cars — even by just one-quarter — new urban areas will be kinder to the environment and provide an improved lifestyle for residents.
The 15-minute city is a well-rounded urban planning concept that stands in stark contrast to sprawling cities.
The fundamental rule is to build communities rather than just new homes. This includes commerce, restaurants, and culture, all no more than a 15-minute walk or bike ride away. Within accessible reach of housing should be workplaces, schools, healthcare, retail, culture, and parks.
It’s clear that a decentralised 15-minute city offers convenience, but it also provides a higher quality of life through improved accessibility, local economic benefits, lower car usage, reduced air pollution, better mental and physical health, and a greater sense of community.
These policies, among others, can help reduce sprawl without compromising necessary development.
Suburbanisation might seem like a simple solution to growing populations and local economic growth, but eating into surrounding agriculture and nature can expose worrying consequences for residents and the environment.
Suburbanisation is associated with water and air pollution, traffic congestion, decreased agricultural capacity, increased car dependency, detrimental health effects, increased flooding, and loss of natural habitats and wildlife space.
Strong planning policies can concentrate urban growth within targeted boundaries and combat uncontrollable sprawling developments.
This type of development is called ‘smart growth’ or ‘new urbanism’ and aims to provide more public space, pedestrian-friendly communities, increased transport options, unique developments, and affordable housing in central areas. These policies, among others, can help reduce sprawl without compromising needed development.
When the automobile was developed and became accepted in the 1920s, populations were no longer restricted to city centre living since they could now transport themselves. In the decades that followed, the construction of highways allowed city planners to encourage developments away from cities.
Since then, urban sprawl has grown due to demographic changes, poor planning, increased incomes, individual preferences, and affordable housing.
Urban sprawl is the expansion of urban developments across a territory. The outward growth, which can extend for miles beyond the heart of the city, creates lower-density settlements on large plots of land surrounding the city.
The population of cities around the world is set to double between now and 2050, but continuing to expand urban boundaries at the current rate is unsustainable and brings challenges for planners.
Once built, a city’s form and links are locked in for generations, which makes it paramount for planners to make decisions that work now and in the years to come.
Eradicating current methods of expansion in favour of liveable, green, high-density cities with fewer personal vehicles is the goal for cities across the world.
Despite benefiting residents with comparatively cheaper housing than city centres, suburbanisation brings many environmental, social and economic concerns.
It’s the negative effects, such as poor public transport, traffic congestion caused by personal vehicles, increased air pollution, and limited community life that lead to an overall negative perception of urban sprawl.
At Bolt, we envisage a world where cities are made for people, not private cars. Whether it’s an e-scooter, e-bike, flexible ride-hailing or shared rental cars, Bolt offers transport options to reduce private car dependency.
Using the Bolt app, you can choose whatever mode of transport is best for the occasion.
A research project shows that Bolt’s travel options can significantly reduce the number of private cars in the city and lead to a more liveable city in almost every way!
