Urban Land Use Models
The relationships between transportation and land use are rich in theoretical representations that have significantly contributed to regional sciences. They can be investigated empirically through the observation and analysis of real-world changes in the urban spatial structure. However, empirical investigations cannot readily be used for simulation and forecasting purposes. For that purpose, the relationships between transportation and land use can also be investigated through models trying to synthesize the spatial structure through a series of assumptions about urban dynamics.
Since transportation is a distance-decay altering technology, the spatial organization is assumed to be strongly influenced by the concepts of location and distance. Several descriptive and analytical urban land use models have been developed over time, with increased levels of complexity. All involve some consideration of transport in the explanations of urban land use structures. Changes are commonly the outcome of location decisions such as building a facility (residential building, warehouse, store, office tower, etc.) or a transportation infrastructure (road, transit line, port, airport, etc.).
a. Early models
Von Thunen’s regional land use model is the oldest representation based on a central place, the market town, and its concentric impacts on surrounding agricultural land use. The model was initially developed in the early 19th century (1826) for the analysis of agricultural land use patterns observed in Germany. The concept of economic rent is used to explain a spatial organization where different agricultural activities are competing for the usage of the available land. The closer a location is to the market, the lower the transportation cost and availability of land. The underlying principles of this model have been the foundation of many others, where economic considerations, namely land rent and distance-decay, are incorporated. The core assumption of the model is that agricultural land use is patterned in the form of concentric circles around a market that consumes all the surplus production, which must be transported. It is this transportation cost that bears the most influence for the purpose the land will be used. The closer the market, the higher the intensity and productivity of agricultural land use, such as dairy products and vegetables, while the further away, less intensive uses such as grain and livestock dominate. Many empirical concordances of this model have been found, notably in North America.
Another range of early models, such as Weber’s industrial location model developed in 1909, dealt with industrial location, in an attempt to minimize the total transportation costs of accessing raw materials and moving the output to the market, which indicated an optimal location for the activity to take place. The main principle explored by early models is that locational choice and the resulting land uses are primarily influenced by transportation costs. This assumption is not surprising since, in the late 19th Century and the early 20th Century, land transportation options were limited and of the relatively high cost.
b. Concentric urban land uses
The Burgess concentric model was among the first attempts to investigate spatial patterns at the urban level in the first quarter of the 20th century. Although the purpose of the model was to analyze social classes, it recognized that transportation and mobility were important factors shaping the spatial organization of urban areas and the distribution of residential choices. The formal land use representation of this model is derived from commuting distance from the central business district, creating concentric circles. Each circle represents a specific socioeconomic urban landscape. This model is conceptually a direct adaptation of the Von Thunen’s model to urban land use since it deals with a concentric representation, which considers a transportation trade-off between the cost of commuting and the cost of renting housing. Therefore, if the cost of commuting declines due to improvements (e.g. new transit lines), the outcome is that more people can afford to live further away, which results in urban sprawl. Even close to one century after the concentric urban model was developed, spatial changes in cities such as Chicago are still reflective of such a process.
c. Polycentric and zonal land uses
Sector and multiple nuclei land use models were developed to take into account numerous factors overlooked by concentric models, namely the influence of transport corridors (Hoyt, 1939) and multiple nuclei (Harris and Ullman, 1945) on land use and growth. Both representations consider the emerging impacts of motorization on the urban spatial structure, particularly through the beginning of suburbanization and the setting of polycentric cities. Such representations also consider that transportation infrastructures, particularly terminals such as rail stations or ports, occupy specific locations and are also land uses. In the second half of the 20th century, the construction of airport and container port complexes created new nodes around which urban land uses developed.
d. Hybrid land uses
Hybrid models are an attempt to include the concentric, sector, and nuclei behavior of different processes in explaining urban land use. They try to integrate the strengths of each approach since none of these appear to provide a completely satisfactory explanation. Thus, hybrid models, such as that developed by Isard (1956), consider the concentric effect of central locations (CBDs and sub-centers) and the radial effect of transport corridor, all overlaid to form a land use pattern. Hybrid representations are also suitable to explain the evolution of the urban spatial structure as they combine different spatial and temporal impacts of transportation on urban land use, such as concentric and radial impacts.
e. Land use market
Land rent theory was also developed to explain land use as an outcome of a market where different urban activities are competing to secure a footprint at a location. The theory is strongly based on the market principle of spatial competition where actors are bidding to secure and maintain their presence at a specific location. The more desirable a location is, the higher its rent value and the intensity of activities. Transportation, through accessibility and distance-decay, is a strong explanatory factor on the land rent and its impacts on land use. Conventional representations of land rent leaning on the concentric paradigm are being challenged by structural modifications of contemporary cities that were identified by hybrid models.
The applicability and dynamics of land use models are related to issues such as the history, size, and the locational setting of a city. For instance, concentric cities are generally older and of smaller size, while polycentric cities are larger and relate to urban developments that took place more recently. This also includes the impacts of public transit systems that can vary according to the level of automobile dependence. While most of the conceptual approaches related to the relationships between transportation and land use have been developed using empirical evidence related to North America and Western Europe, this perspective does not necessarily apply to other parts of the world.
Dualism has been observed in cities in developing economies where processes such as economic development and motorization are creating an urban landscape that is common in advanced economies. However, an informal landscape of shantytowns represents a land use structure that is not effectively captured by conventional land use models. It remains to be seen to what extent globalization will favor a convergence of land use patterns across the world’s cities. Irrespective of the urban context, standard technologies such as the automobile, construction techniques, information technologies, and managerial practices (e.g. urban planning or supply chain management) are likely to homogenize the land use structure of global cities.