Central business district
From Wikinfo
The Central Business District and its Internal Regions
Introduction: The central business district (CBD) has traditionally symbolized the socioeconomic vitality and strength of the city. It is often thought of as the heart of the city and often found in the CBD is the greatest concentration of offices and retail stores with the highest land values. The definition of the CBD was greatly influenced by the ideas of Murphy and Vance, Ernest Burgess, Homer Hoyt, R.D. McKenzie, and Harris and Ullman.
Historical Evolution The Greek agora, or market place, was the precursor of the modern CBD. The Royal exchange, established in the 1560s in London was perhaps the nucleus of the first modern CBD. In New York City the original settlement occurred near the docks in lower Manhattan and specialized in wholesale functions and gradually expanded in that area. Retail activity gradually emerged along main streets in most cities and/or at rail transport terminals. Location and Size of the CBD The CBD is usually in the oldest part of the city. And has usually undergone several periods of redevelopment. The CBD typically grows toward the higher-income side of the region and a discard zone or space develops on the other side of the CBD. The intensity of the CBD was traditionally dependent upon the era in which the city developed. Older 19th century cities usually display a very high CBD density CBDs emerging after that time period usually have lower land use densities.
The core of the CDB can be deciphered using the Peak Land Value Intersection. The peak land value is usually located at the major intersection of the main streets. Land values and uses are often hypothesized to be the most intense for frontages.
Shape The shape of the CBD varies from city to city. The shape normally responds to the city street plan. In some instances, the CBD is square and rectangular, consisting of several blocks surrounding the PLVI. Assuming there is a grid street pattern and no single dominate street corridor. The CBD can also be elongated along one or two major arteries if they are more important than cross streets. Frequently the CBD is cut off on one side by a physical feature, such as a river or lake.
Centrality The convergence of transportation lines in the area and the many activities that have evolved in response traditionally made the CBD the center of action and prestige. Population and Work Force Trends The modern downtown business district is primarily a work center and has relatively few permanent residents. The CBD had the function as the workplace of the city. Different Concepts of the CBD Ernest A. Burgess and Park had the idea that growth takes place along broad successive zones. They saw the �...central business district [as a] city center...the focus of its commercial, social, and civic life�� They termed the area framing the central focus the �zone of transition� The zone of transition was recognized as an area of high land values because of its nearly central location, characterized by deteriorating buildings. Homer Hoyt was a critic of Burgess, but respected his theory of the CBD and introduced two new elements to the theory. The effects of land pricing or rent The influence of major transportation routes on the pattern of urban growth Hoyt theorized that as a city center grew competition for land at the center of the city resulted in land valued so high that only business could afford the land and the CBD resulted. R.D. McKenzie, Harris and Ullman studied the CBD and presented a multiple nuclei model of the CBD. The CBD is a nucleus of the larger and within the CBD there are several sub-nuclei. The financial district, theater district, and other comparable developments are visible manifestations of the sub-nuclei. This was a more flexible concept and it called to attention the fact that urban areas may have many centers and that new centers of activities or sub-nuclei may develop within existing nuclei.
Delimiting the CBD Raymond Murphy and James Vance Jr. are most often associated with their work on the delimitation of the CBD. Their definition of the CDB includes two indexes A central business height index. That is calculated based on the ratio of the total ground floor space of a block to the floor area occupied by CBD uses. A central business intensity index. That is determined by dividing the total floor area in the block devoted to CBD uses by the total block floor area. Blocks with high values on these two indexes form the CBD. Peak land value intersection is used to decipher the core of the CBD. The peak land value is usually located at the major intersection of the main streets. Land values and uses are often hypothesized to be the most intense for frontages. The Core-Frame Method The core-frame method used to define the CBD is a more conceptual approach. The core is the most intensely utilized part. The frame is the surrounding support area. The core is distinctive for its high-rise structures, business linkages, pedestrian traffic, limited parking space, and near complete use of sites. The frame is typically composed of warehouses, parking lots, medical services, light industry, and wholesale functions. There is a continuous movement of CBD territory over time. The CBD typically discards older, run-down structures, characterized by marginal retail business and skid row uses, and higher income uses of the city. These areas are known as the zone of assimilation and the zone of discard. Functional Areas There are several functional sub-areas in the CBD: Core Office Function The growth of the CBD office function was offset by the decline of the retail economy. Offices clusters in the CBD to take advantage of the accessibility of the downtown area fro large concentrations of workers. Medical District Government function Skid row Functions as a haven for the homeless and societal �dropouts� and as an area for adult entertainment. It is typically part of the zone of discard. Wholesaling and Warehousing
A.McNair October 14, 2003
