What is urban planning?
Urban planning is both a technical and political process that seeks to regulate the form and growth of human settlements. This process often involves collecting data about the current state of the settlement and forecasting future growth and change. By doing so, urban planners aim to guide development in such a way as to meet certain objectives, such as promoting sustainability, encouraging economic development, or enhancing social justice. Urban planners use their technical expertise in planning to inform local policy makers.
Common goals of urban planning include:
- Protecting the health and safety of residents
- Mitigating social and environmental problems
- Regulating new development and infrastructure to meet local objectives
- Ensure compatibility among land uses
- Project future growth and anticipate/plan for challenges
A brief history of urban planning
The deliberate planning of cities dates back at least 5,000-6,000 years. There’s evidence that the Sumerian cities in Mesopotamia (i.e. the fertile crescent) purposefully laid out roads and reserved areas of the city for specialized purposes. This was particularly true of the administrative/religious center, which typically housed the temple (often a ziggurat) , palace, and shine. Egyptian cities too were planned around administrative/religious centers and sometimes featured grid road networks.
By the classic era, urban planning had grown in complexity. The Romans borrowed and expanded upon ideas of urban planning developed by the Greeks. In Rome, there were several master-planned administrative areas of the city, known as forums, built over several centuries. By 100 AD Rome had expanded into a massive empire, with new settlements and outposts either conquered or newly founded on a regular basis. The provincial towns were often planned around administrative areas, baths, entertainment venues, and frequently featured efficient, regular road networks. As master builders, the Romans also constructed elaborate water and sewer systems to meet the needs of a burgeoning population.
While urban planning was limited mostly to defense during the Medieval period in Europe, many prominent Asian cities continued to be precisely arranged around an administrative center. It wasn’t until the 19th century, if fact, that significant, large-scale planning returned to European cities. Baron Haussmann’s redevelopment of Paris was perhaps the most prominent example of large-scale planning in Europe at the time. Much of what we associate with Paris today — the wide, straight boulevards, monuments, and spectacular urban vistas — were created in the mid-19th century.
To accomplish this task, the state under Napoleon III had to acquire and demolish large sections of the city. While boulevards were being built to reduce over-crowding and congestion, Haussmann also laid sewer, water, and gas pipes; laying the foundations for a modern metropolis (i.e, Paris as “the city of lights”). The ideas of renovating, redeveloping, and even relocating urban development were popular means of regulating urban settlements well into the mid-20th century.
In the United States, the construction of skyscrapers in New York in the early 20th century promoted the first city-wide zoning regulation. By 1916, buildings were becoming so tall the tended to block light and restrict airflow at the surface. To reduce their impact, New York City instituted set-back requirements for new buildings, which restricted how much of their lot they could occupy at a given height. This resulted in the tiered or “layered cake” style of 1920s/30s art deco skyscrapers.
Finally, zoning became a widespread mechanism for local and state governments to control land use following the Supreme Court case Euclid vs. Ambler realty in 1926. Ambler Realty wanted to build an industrial plant in the heart of Euclid, OH, a mostly residential neighborhood outside of Cleveland. Through a series of court battles, culminating in the Supreme Court case, Euclid was granted the ability to control the use of private land through zoning in support of residents’ health and welfare.
Land use planning & zoning
The practice of urban planning today largely centers around the regulation of land use and land development. Urban planners are charged with determining the most appropriate use of both public and private land, and most often impose such regulations through zoning laws. The primary goal of zoning has historically been to separate “incompatible” uses. While zoning initially only excluded residential and industrial land uses, by the mid-20th century it was common to segregate residential and commercial land uses as well. Recently this has begun to change with mixed residential/commercial zones (i.e., “mixed use”) becoming more common.
Standard euclidean zoning (named after Euclid, OH, not the mathematician!) is the most strict form of zoning, which not only separates residential, commercial, and industrial land use, but also single-family and multi-family residential. Buildings and individual land parcels are often regulated as well through restrictions on building heights, setbacks, and minimum lot sizes.
Smart zoning is a more flexible an alternative to euclidean zoning that allows for planned-unit developments (PUDs) with mixed residential and commercial land use or mixed light industrial and commercial land use. It also permits cluster zoning in which residential units can be arranged in a more dense fashion than normally allowed in order to preserve green space.
It is form-based codes, however, that offer the most comprehensive and flexible alternative to standard euclidean zoning. With form-based codes, there is no absolute restriction on the type of land use. Instead, it seeks to regulate the form of the new development by specifying the size and layout of buildings and their setbacks, as well as accessory features such as lighting and vegetation.
The master plan
Most urban planning departments are charged with forecasting future growth and the various challenges and opportunities that lie ahead. This also means preparing for growth by developing future land use plans and working with other city departments and utility organizations to most effectively accommodate future change. Often, a master plan is developed to formally address these issues.
It’s common for larger cities in particular to have extensive master plans (or comprehensive plans) with several sub-sections to address specific issues such as the environment, housing, transportation, land use, public facilities, infrastructure, parks/recreation, and policy goals such as sustainability or economic development. Models of growth and future land use change are often mapped to better visualize, interpret, and plan for new development.
Although the field of urban planning is constantly changing based on new information, best practices, and new policy goals, ultimately planners strive to enhance urban residents’ quality of life by managing the form and use of land in the city.