One method of
zoning land for
development and
use. The idea behind single-use zoning is to assign a section of land as being used solely for
residential,
commercial, or
industrial purposes. (This should be quite
familiar to all persons familiar with
SimCity) Land designated for one use
cannot be used for other purposes.
Single-use zoning started appearing in the 1920's, in the United States, as a change from the mixed-use zoning that had been the case long before then. Suddently, land was being set aside for a single purpose, and usually in large, sweeping tracts. No longer would there be buildings with grould-floor businesses and upper-story residences. A building would either entirely for living, or entirely for business purposes.
It was the automobile that really enabled this method of zoning. Before the automobile, people had to rely on walking, public transportation, or a horse-drawn carriage. Because of what was involved with horses, this more or less required people in the city to live near where they shopped and worked, so there was a necessity to mix all the various types together. This led to the establishment of well-defined and known neighborhoods that people didn't have to venture out of for their needs.
After the automobile, it became possible to travel longer distances for shopping, entertainment, and work. Some people started to desire leaving the city, finding the less dense and busy lands a ways away, and living there, commuting. The growing demand gave rise to zoning for large residential areas - and often the residential zoning even specified whether there would be single-family homes, multi-family homes, or apartments. As the people migrated out, there arose the opportunity for commercial areas nearby the residential ones, and keeping with the new idea of single-use zoning, the stores were seperate from the housing.
This method of zoning was also influenced by the desire to move highly-polluting factories and industrial plants away from residential areas to improve quality of life. This is still considered a good thing - nobody wants to put a power plant in the middle of residential neighborhoods.
The single-use zoning of residential and commercial areas has directly resulted in surburban life today. Large tracts of housing, surrounded by large arterial roads to handle the large amounts of automobile traffic. These roads offer a perfect audience to sell things to, so commercial areas arise along these roads, increasing traffic. Industrial areas, where so many people work, are tucked in pockets in out of the way places, or even better, in another community. Thus commuting becomes necessary, and congestion.
As the zoning continued, urban sprawl started to form, and the decline of the third place. Some people are trying to fight against single-use zoning, feeling that the sprawl and lack of community it forms are harmful to the culture of the area, and even the country, as people lose their connections with each other.
Single-use zoning has caught on around the world, and is not even limited to cities with high numbers of privately-owned automobiles. Any city with a transportation system capable of moving significant numbers of people between residential, commercial, and industrial areas can make use of single-use zoning, with varying results.
There seem to be few arguments in favor of single-use zoning, but it remains so popular because it's taught to civil engineers and city planners as the way to do things, and the inertia of years of doing it that way. It's become so ingrained as the only way to zone that even the computer game SimCity only allows single-use zoning. There's also the surburban population, having mostly grown up in such areas, that often don't consider the possibility of anything else. Points in it's favor may include the fact that more mixed-use zoning would discourage single-family homes, and make the ones that do get built more expensive, as otherwise more could be done with the land. Though some might not consider those to be bad things.