Increasing Density

By Viban Gonzales

Introduction

As the world population continues to grow, cities need to keep up with the large numbers of people moving in. Some cities respond to population growth by developing further and further from the city center. This leads to urban sprawl, which is defined as “low-density, land-consuming, automobile-dependent, haphazard, non-contiguous (or ‘leapfrog’) development on the fringe of settled areas, often near a deteriorating central city or town, that intrudes into rural or other undeveloped areas”.¹

Urban sprawl is inefficient and has negative effects on people and the environment. It leads to a reliance on private car ownership which creates serious public safety hazards, plays a role in stress, depression, high levels of lung disease and asthma in urban areas, and raises energy and labor costs and lowers productivity.² Urban sprawl also makes it difficult to have a reasonable work-family balance, especially for women—commuting to and from work, picking up and dropping off children at school and after-school activities, running errands and visiting the doctor becomes time consuming when each location is far away.³ It contributes to air pollution, loss of wilderness and farmland,¹ environmental degradation, and global warming.²

A solution to urban sprawl is to increase density within the city instead of building out. This can be achieved through the use of mixed-use zoning, the limiting of road footprints, and the construction of taller buildings. Although time-consuming and costly, implementation of these solutions will be worthwhile.

Solutions

Mixed Use Zoning

Euclidean zoning, or single-use zoning, emerged during the industrialization of America³ and became the primary method of regulating land use.⁴ It was developed in order to deal with the diseases and spread of epidemics that were partly caused by the lack of separation of uses.² Advances in public health and medicine make this reason largely irrelevant today. Under Euclidean zoning, industrial, commercial, retail, civic, and residential³ areas are separated. Cars or long rides on public transportation become necessary to run errands or go to school or work. This especially impacts working women with children, as the long distances required to travel often puts pressure on the work-life balance; this can result in the decision to quit work and become stay-at-home mothers³. Single-use zoning allows for “low density development with a high separation of uses”¹, also known as sprawl.

In contrast, mixed-use zoning combines several of these land uses in one area. This type of zoning allows for compact development and considerably reduces the reliance on cars.³ Instead of building out from the edge of cities, growth can be focused within.

Mixed-use areas increase commercial activity⁵ and are safer and less crowded during busy periods.¹ This type of zoning encourages people to walk more and drive less, meaning a greater number of people on the streets; it’s easier to walk down a road with many people compared to an eerie deserted one. And since commercial establishments are more spread out, people aren’t concentrated in a comparatively smaller area that is designated for commercial use. Jobs are closer to home, allowing women to work while raising children.³ This type of zoning also mitigates the problems that single-use areas face, such as environmental and energy problems, the deterioration of city centers, and racial and socioeconomic segregation; affordable and expensive housing are mixed and spread out in a city instead of zoned off in distant areas, and the placement of businesses nearby allows people of different socioeconomic status to have a reason to visit more affluent neighborhoods.¹

However, there are some cons to mixed-use communities. People living in close proximity to industrial areas may be exposed to pollutants that cause negative health effects such as “high levels of cancer, birth defects, asthma, respiratory disease, hearing loss, lack of sleep and stress.”² It is apparent that due to hazardous materials, some industry should not be located near residential areas.

Toxic industry tends to be located more often in mixed-use communities that are low income and/or predominantly inhabited by minority groups; this is partly due to the fact that these communities have barriers to participation in the blocking of this use.² Barriers to access include expectations about who has a ‘voice’, foregone work, time constraints, and corruption.⁶ Poor people tend to not be able to afford to take time off from work and spend it participating in public decision-making. And even if they did, the expectation that their voice won’t be heard because of their social status or corruption makes participation seem futile.

Case Study: Paris¹

In Paris, mixed-use zoning is the norm and even encouraged. The aspects that zoning codes control are mostly aesthetic ones (maximum building heights, materials that take fire into consideration, minimum courtyard sizes for sunlight and air). Many people walk to work since jobs are so close to home. Life is also easier since school, shops, banks, churches, doctors, etc. are within walking distance. These factors lead to a city that is very dense, cohesive, and visually appealing.¹

Figure 1. Paris.

Limiting Road Footprints

When limiting sprawl by increasing density within cities, each area of land is valuable. Much of a city’s surface area is occupied by streets, roads, and highways. Many cities face traffic congestion, and often, the proposed solution is to either build more roads or build more lanes. However, highways require much land and resources and have detrimental effects on neighboring areas such as air pollution and noise.⁷ In addition, building more highways can lead to more congestion, as traffic is “funneled” into one path instead of distributed throughout a network of roads.⁸

In some cases, the removal of highways is beneficial to a city. Drivers are forced to take different routes, distributing traffic instead of concentrating it on one path. The problems of unnecessary energy usage and excessive carbon emissions from idling in traffic are eliminated.⁸ Other benefits include the increase of surrounding property values and reduced crime due to increased foot traffic.⁸ The removal of a highway also opens up the previously occupied land to a wide range of development.

However, highway removal isn’t suitable for every city. The traffic shift from a highway to a network of roads will be burdensome to pedestrians used to lighter street traffic.⁸ And some cities might not have the infrastructure to support highway removal. In this case, other solutions listed should be considered for implementation.

Case Study: Providence, R.I.⁹

The Rhode Island government relocated Interstate 195 from the middle of Providence to the outskirts of the city. This opened up 19 acres of land for development while also reuniting the areas that it once divided. So far, land has been claimed for development for housing, retail, office, and university use. Rhode Island commerce secretary Stefan Pryor believes that the new land will contribute much to the state’s economy.⁹

Taller Buildings

While building outwards isn’t ideal, building upwards is an option. Many cities such as New York City are known for their skyscrapers and iconic skylines. However, opposition from locals that complain about blocked views and sunlight often complicates or completely prevents the construction of new skyscrapers.¹⁰ Some want to prevent a “Manhattanization” of their city and preserve their skyline. But for many cities, constructing taller buildings is necessary to keep up with population growth.

Constructing buildings with many floors isn’t as costly as it seems. It makes sense to add more levels since fixed costs such as site preparation, legal fees, and an architect don’t depend on the number of floors; in fact, after about seven stories, the following floors aren’t that much more expensive to build.¹¹ And recently, advances in engineering technology have allowed skyscrapers to be safely built in earthquake-prone regions.¹²

However, there are many obstacles to constructing tall buildings. Since skyscrapers increase the number of people that are able to occupy a unit of land, space is more affordable; this usually means that property values aren’t increasing to match the demand for space due to population growth, which makes current property owners unhappy.¹¹ This leads to locals strongly opposing the construction of skyscrapers. Careful surveying of land and considerations such as earthquake proofing are important. Bad engineering can be disastrous.¹³ Also, cities that actually can still expand outwards don’t have the incentive to build upwards.

For many cities, it isn’t easy to erect taller buildings. Skyscrapers need a large initial capital investment to come to fruition, and construction requires lots of building materials, manpower, and time (usually years). Sometimes, there is no land available to build on; this scenario forces the destruction of existing buildings or historical sites in order to build upwards. However, a compromise between limiting urban sprawl and limiting destruction could be development on the edge of cities. The AZCA district in Madrid is one example; it was developed in 1969 “in an effort to create a new business district outside the overcrowded city center.”¹⁴ It is home to several skyscrapers.

Case Study: London¹⁵

London’s population is projected to grow to 11 million by 2050, with a high estimate of 13 million.¹⁶ The city will have to erect more housing to accommodate this growth. “There are 436 towers — defined as those over 20 — proposed, in planning, approved, under construction or completed in London, according to research by New London Architecture,” and 73 percent are residential.¹⁷

Conclusion

These solutions — mixed-use zoning, limiting road footprints, and taller buildings — limit urban sprawl by increasing density within cities. However, increasing density isn’t very helpful when other infrastructures such as transportation and waste management aren’t updated to keep up with population growth. The use of these methods must be part of a larger effort to make cities more sustainable and equitable by 2050.