80
H. Nuissl and S. Siedentop
and even regions (e.g. Kolankiewicz and Beck 2001; Lambin et al. 2001; Huang et al.
2007; Creutzig et al. 2019). However, first of all, it is crucial to note that there is
no grand theory of urbanisation or comprehensive explanatory model of urban land
use change that would make it possible to interpret and explain actual observations.
Instead, social sciences and economics have offered various theories that hint at
important drivers of land-consuming human activities.
Neoclassical economic theory in particular has provided a closed framework for
the explanation of urban growth. Basically, it postulates an unregulated land market,
where land rents near the urban core are highest (because of maximum accessibility
to urban services and correspondingly negligible transport costs), and argues that
location decisions by both private households and firms reflect the goal of achieving
maximum utility by balancing space needs, location preferences and financial budget
constraints. Based on these primary considerations, it might be plausible to assume
that high-income groups (with more land-demanding aspirations) would prefer to
live at a greater distance from the city centre where large building lots are available,
while low-income households would choose a location near the urban core which
would incur lower transport costs. Starting from these assumptions, the neoclassical monocentric model of urban spatial structure (the “Alonso-Muth-Mills model”)
explains the spatial expansion of cities and density gradients with just a few variables, specifically the demand for new housing and commercial land, rising incomes,
innovations in intra-urban transport systems, and decreasing transport costs (Alonso
1964; Muth 1969; Mills 1972; Mieszkowski and Mills 1993). This meant that the
growing physical footprint of cities and their declining density was the combined
effect of a growing population, rising affluence and enhanced individual mobility
due to the increasing affordability of the private motor car.
In addition to economic theorising, technical viewpoints underpin the importance
of distance and transport costs with respect to the spatial diffusion of urban land
uses. They associate the compactness of the pre-industrial city with the fact that most
trips had to be made on foot or similarly slow modes of transport. This constraint
disappeared with the availability of faster mass transport technologies and the private
automobile (e.g. Antrop 2004). Following this logic, the physical growth of cities
became a function of transport technology. Nelson (1992) pointed out that other
improvements in technology, such as the personal computer, cellular phones and the
internet, may have encouraged the spatial decentralisation of people and firms even
further, setting up conditions for more land-intensive forms of urbanisation.
Empirical observations of how urban areas develop, such as the emergence of
polycentric urban configurations, often defy the simple assumptions of pure neoclassical urban theory. In contrast to the fundamental assumption in the neoclassical city
model that employment was concentrated in central business districts (and gradually decreased with increasing distance to the urban core), modern agglomerations
in developed countries are characterised by their multi-nodal settlement system,
with a complex pattern of primary and secondary centres (Garreau 1991; Champion 2001; Davoudi 2003). Accordingly, many additional factors other than land
prices and commuting costs have been identified that affect the location decisions
of individual households or firms (Nechyba and Walsh 2004). Examples include the
H. Nuissl and S. Siedentop
and even regions (e.g. Kolankiewicz and Beck 2001; Lambin et al. 2001; Huang et al.
2007; Creutzig et al. 2019). However, first of all, it is crucial to note that there is
no grand theory of urbanisation or comprehensive explanatory model of urban land
use change that would make it possible to interpret and explain actual observations.
Instead, social sciences and economics have offered various theories that hint at
important drivers of land-consuming human activities.
Neoclassical economic theory in particular has provided a closed framework for
the explanation of urban growth. Basically, it postulates an unregulated land market,
where land rents near the urban core are highest (because of maximum accessibility
to urban services and correspondingly negligible transport costs), and argues that
location decisions by both private households and firms reflect the goal of achieving
maximum utility by balancing space needs, location preferences and financial budget
constraints. Based on these primary considerations, it might be plausible to assume
that high-income groups (with more land-demanding aspirations) would prefer to
live at a greater distance from the city centre where large building lots are available,
while low-income households would choose a location near the urban core which
would incur lower transport costs. Starting from these assumptions, the neoclassical monocentric model of urban spatial structure (the “Alonso-Muth-Mills model”)
explains the spatial expansion of cities and density gradients with just a few variables, specifically the demand for new housing and commercial land, rising incomes,
innovations in intra-urban transport systems, and decreasing transport costs (Alonso
1964; Muth 1969; Mills 1972; Mieszkowski and Mills 1993). This meant that the
growing physical footprint of cities and their declining density was the combined
effect of a growing population, rising affluence and enhanced individual mobility
due to the increasing affordability of the private motor car.
In addition to economic theorising, technical viewpoints underpin the importance
of distance and transport costs with respect to the spatial diffusion of urban land
uses. They associate the compactness of the pre-industrial city with the fact that most
trips had to be made on foot or similarly slow modes of transport. This constraint
disappeared with the availability of faster mass transport technologies and the private
automobile (e.g. Antrop 2004). Following this logic, the physical growth of cities
became a function of transport technology. Nelson (1992) pointed out that other
improvements in technology, such as the personal computer, cellular phones and the
internet, may have encouraged the spatial decentralisation of people and firms even
further, setting up conditions for more land-intensive forms of urbanisation.
Empirical observations of how urban areas develop, such as the emergence of
polycentric urban configurations, often defy the simple assumptions of pure neoclassical urban theory. In contrast to the fundamental assumption in the neoclassical city
model that employment was concentrated in central business districts (and gradually decreased with increasing distance to the urban core), modern agglomerations
in developed countries are characterised by their multi-nodal settlement system,
with a complex pattern of primary and secondary centres (Garreau 1991; Champion 2001; Davoudi 2003). Accordingly, many additional factors other than land
prices and commuting costs have been identified that affect the location decisions
of individual households or firms (Nechyba and Walsh 2004). Examples include the