Towards an effect-based model for airport and cities

Full text

13 Towards an effect-based
model for airports and cities
Christian Salewski, Benedikt Boucsein
and Anna Gasco
Limitations of existing models for airports and cities
Large airports are enormous built structures occupying vast areas of land. The
core components of any airport are its runway system, technical facilities, termi-
nal buildings, and buildings for supporting services such as maintenance, freight,
security, boarding, and the landside access system of roads, parking, and rails.
Adding to that are secondary, auxiliary, or enhancing functions such as shop-
ping, hotels, conference centers, offices, and logistics. The central areas around
the terminals of very large airports, often hubs or secondary hubs, can equal or
surpass their mother cities’ central areas in size, as is the case in Amsterdam.
(see Figure 13.1).
By their sheer size alone, airports have a massive impact on the structure and
form of the built environment. They shape the present urban and landscape struc-
ture and give shape to their future development. They do so by conditioning a
much larger area than its direct territory: areas affected by regulations and emis-
sions, the tangle of landside access routes, or airport-related built structures that
may be located far away from the runways. The Dutch historian, Koos Bosma,
and the Russian sociologist, Anna Nikolaeva, have described Schiphol Airport
accordingly “as a deep-pile carpet across which objects, information and people
move. To extend the metaphor, an oddly shaped carpet with frayed edges that
reach deep into the region and with an air column of about 10 kilometers on top
of it” (Bosma and Nikolaeva 2013). Mapping that “carpet” is possible, but never
final, since its form and size vary considerably depending on the factors taken
into account.
Although the great impact of large airports on the built environment is widely
acknowledged, there is no agreed-on categorization of airport-related urbaniza-
tion effects. Urbanization around large airports partly follows known patterns
that can be found elsewhere in urban peripheries, in urban sprawl, and on urban
edges. But large airports also produce their own urbanization patterns due to the
specific nature of their effects. To learn more about these patterns, a comprehen-
sive comparison is misleading; airports and their urban regions are always
unique, shaped by long, specific histories of urban and airport development,
topography, politics, and culture. In this chapter, we therefore chose a different

258 Christian Salewski et al
approach and propose a categorization not of airports and their city regions, but
of effects that can be observed in all cases to different extents. The aim of this
approach is to introduce a frame that helps to analyze urban conditions around
large airports. It can thereby inform urban design and improve planning inter-
ventions and policy decisions. We found this necessary because we found that
existing models are either too abstract or too normative for such purposes.
In the discourse – both in academia and in praxis – two kinds of models exist
to explain and explore the impact of airports in their relation to cities and regions.
One kind are city models that describe the urban structure shaped by airports, to
which we will turn later. The other kind are mathematical models that calculate
economic effects of airports on their city regions. The economic impact of air-
ports on their urban regions is substantial, but difficult to measure in its totality.
Starting with Airport Council International Europe’s report on economic effects
of airports from 1998, a classification into the four categories of direct, indirect,
induced, and catalytic economic effects has been used by most, if not all, eco-
nomic impact studies (ACI Europe 1998). These categories count financial
effects that are functionally related to the airport: direct effects are spending for
Figure 13.1 To scale collage of Amsterdam city center on Schiphol Airport
Source: Authors’ research.

Towards a model for airports and cities 259
aviation, indirect effects are spending supporting aviation and spending by trave-
lers, induced effects are spending caused by the demand of employees in the first
two categories. Catalytic effects measure increased productivity in specific eco-
nomic sectors that profit of enhanced accessibility, notably in advanced services
and knowledge-intensive industries. Some models include negative impacts of
emissions on housing prices and rents. Except for setting geographic system
boundaries to limit data, most economic models largely ignore the spatial distri-
bution of effects and their impact on the built environment. Instead, they yield
aggregate financial effects related to aviation, allocation, and urbanization.
To gather support for airport operation, airport extension, or to counter initia-
tives that want to limit aviation to reduce noise, economic models are widely
used. However, this poses a dilemma: economic models show benefits that they
cannot precisely locate in their impact, while most negative effects – mainly of
noise – are precisely located. Negative and positive effects seem thus unevenly
distributed in space; while positive impacts of allocation and urbanization effects
are expected to take place somewhere in the wider airport region, negative
impacts are more concentrated at and around the airport itself. Proponents and
opponents of airport operation therefore often work with incompatible problem
frames: a diffuse distribution of economic benefits versus homeowners and rep-
resentatives of specific urban communities.
Besides economic models, the other category used to explore the impact of
airports on the built environment are city models. In urban design, a city model
is a concept and idea that captures the basic characteristics of an urban structure.
City models have always been part of thinking about cities. They include all
aspects of a city in a concise sketch and a brief description. (Lynch 1981)
According to the American urban planner, Kevin Lynch (1918–1984), city mod-
els are always normative, showing how the city ought to be, not how it is.
Normative models serve as shared frames for decision makers. They are more
abstract than development visions for specific urban situations and help to com-
municate the basic qualities strived for. For airports and their urban environ-
ments, a number of such city models have been introduced, but notably three
have been most influential: the airport city model, the aerotropolis model, and
the airport corridor model (Freestone and Baker 2011) (see Table 13.1). These are
normative city models that are essentially descriptions of geographic distribution
Table 13.1 Influential program-based conceptual models for airports and cities
Airport City
(Schiphol Group)
Non-aviation centered, mixed-use programs of high density and
gniklaw ni dna lanimret tropria eht ta yltcerid noitaerc eulav hgih
distance, in most cases entirely on the airport territory.
Airport Corridor
(Schaafsma et al.)
A transfer of the Airport City model onto the corridor between the
airport and the mother city.
Aerotropolis
(Kasarda)
Clustering of aviation-centered logistics and production in a
concentric pattern around an airport city.
Source: Authors’ own.

260 Christian Salewski et al
of airport-related programs. In their choice of programs, airport city, aerotropo-
lis, and airport corridor mainly follow the reasoning of the economic models.
The airport city describes the mixed functions at the airport terminal described by
indirect effects (Güller and Güller 2003). The aerotropolis includes the airport city
and encompasses a wider array of logistics, advanced services, and knowledge-
intensive industries in a concentric structure around the airport (Lindsay and
Kasarda 2011). Some housing is also included, but not a central concern of the
model. The airport corridor also includes the airport city and focuses primarily
on the location of advanced services between the airport terminal and the mother
city (Schaafsma et al. 2008).
However, city models can also be descriptive, that is, explain how the city is,
how it evolved, and how it functions. Such descriptive models are, for example,
Thomas Sievert’s “Zwischenstadt” (in-between-city) describing urbanized land-
scapes, or Joel Garreau’s edge city, a term coined for exurban business and retail
clusters (Sieverts 1997; Garreau 1991). To explore the relation of airports and
cities, such descriptive models bear more potential than normative models: they
can frame problems and potentials of airport and urban development based on
real situations, and they can serve to translate findings from one situation to
another. Descriptive models also pose less danger of providing an airport-biased
view on the urban structure that ignores other important influences on the urban
structure.
The three normative city models for airports do not – and cannot – substantiate
the link between economic models and concrete, local spatial impact. The eco-
nomic models that they are based upon work on aggregated data and are hard to
confirm on the ground. This seems not least due to multi-criterial locational
decisions of firms, which state that the airport is one important reason, but usu-
ally not the decisive one for locational choice.1 To better understand the effects of
large airports on cities, we therefore find it necessary to elaborate an approach
that leads towards a descriptive city model that is more precise concerning the
geographic distribution of both positive and negative effects. Such an approach
will eventually need to combine different perspectives, notably including eco-
nomic, social, political, and environmental effects. As urban designers, we start
with a categorization of effects of large airports on the built environment and a
description of resulting urban conditions. The following discussion is based on
our ongoing research on the three cases Amsterdam, Zurich, and Singapore.
While all three have hub status, they vary greatly in many other respects.
Together, we found them to be excellent examples to illustrate our concepts: all
are located close to their mother city center, while the planning regimes are tra-
ditionally different and have, hence, led to different, yet typical, situations of
integration of airport and urban development (see Table 13.2).
For further investigations, a larger set of cases will need our attention. More
research into underlying issues of governance and agency is necessary to under-
stand how they condition the specific performance of effects on the built envi-
ronment. These issues also require a more diachronic approach that compares
different development pathways of airports and their city regions. For now, our

Towards a model for airports and cities 261
arguments may therefore be regarded as preliminary, a framework for future
works. They are a description of what we found in our three cases.
Categorization of effects of the airport on the built
environment and affected areas
Airports and cities come in great variations of size, kind, and location. For an
investigation of the effect of airports on the built environment, the distance of
airport to city center is important; if the airport is close to or within the built-up
structure of the city, the effects are more explicit than for an airport located far
out. We propose a categorization of effects of airports on the built environment
that is most clearly visible in urban airport areas. We found that airports have
substantial effects on the urban and landscape structure in mainly five ways: ter-
ritorial effects, aviation effects, flows effects, allocation effects, and urbaniza-
tion effects. In the following, we explain these effects and the respective affected
areas and illustrate these for the cases Zurich, Amsterdam, and Singapore. We
thereby deduce several area types depending on effect type.
The territory of the airport itself and its close vicinity are affected by territo-
rial effects. These are mainly threefold: the interruption of connecting ground
networks, the blocking of urban development, and the spatial distortion of urban
structure around the airport.2 The area affected is the airport territory, the land
governed by the airport including airside and landside, and its airport periphery.
Depending on the specific situation, the airport periphery may extend up to a few
kilometers from the airport, for example by rerouting of highways or compres-
sion of urban development. An example for this distortion is the routing of high-
ways around Amsterdam Airport or the Flughafenstrasse between Kloten and
Rümlang in Zurich, which had to be built when the airport cut off the traditional,
direct connecting road (see Figures 13.2, 13.3 and 13.4). Airport territory and
airport periphery together amount to what Hubstart Paris has termed the “airport
area” (Hubstart Paris 2011).
A survey of the location of Europe’s 99 largest airports by passenger numbers
(more than 3 million passengers per year) revealed that about 45 percent were
located within or attached to the built-up urban structure of the city in a distance
Table 13.2 Typical situations of urban regional integration of airports and city regions
High integration of physical
urban development
Low integration of physical
urban development
High integration of
gninnalp ralacs-retni
and decision making
High (Amsterdam) Notional (Singapore)
Low integration of
gninnalp ralacs-retni
and decision making
Factual (Zurich) Low (or Accidental)
(Munich)
Source: Based on Salewski et al. (2011: 10).

262 Christian Salewski et al
of less than 15 kilometers to the city center (ETH Zurich Airports and Cities
et al. 2010) (see Figure 13.2).
We propose to use the term urban airport area to describe their condition,
since the airport area is factually located within the city, at least partially (see
Figure 13.5).
Aviation effects affect mainly the area inside the noise contour, of which sub-
stantial parts usually consist of landscape kept free of building due to emissions
or security restrictions.
No-bird zones limit the surface areas of artificial bodies of water; building
heights are limited around the runways (see Figure 13.4). We therefore call this
area noise landscape, even if it includes built-up structures. In most cases, the
noise contour leads to planning regulations that limit the possibility of building.
Therefore, urban development can be compressed right outside the noise landscape.
This is an effect we call noise contour inversion and stretches further out from the
noise landscape in an irregular form depending on the specific urban situation. In
Amsterdam, the noise contour limits the urban expansion of Amsterdam towards
the south-west, while the noise landscape of the Haarlemmermeerpolder is devel-
oping into a juxtaposition of agriculture, infrastructure, logistics, and low-density,
Figure 13.2 European airports with urban airport areas
Source: Based on ETH Zurich Airports and Cities et al. (2010), Ein Atlas Europäischer Flughafen und
Städte, ETH Zurich, Chair for Architecture and Urban Design, Prof Kees Christiaanse.

Towards a model for airports and cities 263
non-residential programs. In Haarlemmermeer, noise contour inversion has shaped
the urban edges of Hoofddorp and Nieuw-Vennep by keeping the area in between
free from further housing development. As part of the noise landscape, that area is
now subject to a large-scale transformation project that will turn it into a regional
park (Municipality of Haarlemmermeer 2013). Aviation effects depend not least on
topography; at Singapore Changi Airport, the noise contour extends mainly over
water and has therefore very limited effects on the built environment.
Flows effects can be found on a large range of scales from the airport area up
to national and international scale. Airports create, concentrate, and divert sub-
stantial critical flows, notably people, cargo, energy, waste, and water. Depending
on the f lows, the affected area can be very different. For waste processing, for
Figure 13.3 Zurich urban airport area
Source: Authors’ research.
Notes: Aviation effects (noise contours, height limitations), (1) airport front side with emerging airport
corridor, (2) airport backyard, (3) Limmattal development corridor.

Figure 13.4 Amsterdam urban airport area
Source: Authors’ research.
Notes: Aviation effects (noise contour, height limitations, no-bird zone), (1) airport front side, (2) airport
backyard with airport tangent, (3) noise contour inversion between Hoofddorp and Nieuw-Vennep.
Figure 13.5 htfif s’lohpihcS ot ytimixorp sti ot eud dehsilomed gnidliub a fo snoitadnuoF
runway, the Polderbaan
Source: Authors’ research.

Towards a model for airports and cities 265
example, Amsterdam Airport’s affected area stretches out to Rotterdam,
Maastricht, and Lelystad (Geldermans et al. forthcoming). Energy networks
extend far beyond national borders. It is therefore not possible to relate one spe-
cific area to flows effects; for each aspect, a specific area needs to be distin-
guished. Probably the most important f low effect concerns passengers. These
require high-capacity landside access transport systems for the airport. Such sys-
tems not only enhance the airport’s accessibility for passengers and employees,
but also regional – and sometimes local – accessibility. Passenger flows can lead
to the allocation of non-aviation programs at the airport, depending on the govern-
ance of the city region. In Singapore, the strict control of urban development by
the centralized Urban Redevelopment Agency (URA) has so far prevented such
allocations at Changi Airport. In contrast, the airports of Zurich and Amsterdam
have attracted non-aviation programs as part of their business model. In contrast
to Changi, they have also evolved into landside transit hubs with nationally,
regionally, and locally important railway and bus stations. In the case of Zurich,
23.7 million landside passengers per year almost equaled 24.3 million aviation pas-
sengers in 2012 (Häne 2012). While this may lead to higher peak loads for public
transport, it also enhances connectivity for the airport – the hub model in aviation
applies in principle also to the landside (Orth and Weidmann forthcoming).
Allocation effects concern firms that are related to aviation and firms that
profit from access to the airport. The latter make up the core argument in eco-
nomic models; airports increase productivity and competitive advantage of their
region through enhanced global accessibility and connectivity.
This pushes economic growth and leads to the allocation of new firms. With
the exception of very few firms that do need geographic proximity to the airport,
allocation effects are distributed unevenly within the airport region or catchment
area, which can extend – depending on the necessary frequency of air travel for
business – to about 3 hours of commuting time.3 Within the airport region, many
more factors influence the choice of location of firms: availability and price of
land and real estate, landside accessibility and connectivity, proximity to ade-
quate housing areas and other urban services, and proximity to connected or
related other firms and institutions that support the business, for example through
local supply chains or clustering (see Figure 13.6). Allocation effects can leap-
frog geographic and administrative boundaries. An example is the emergence of
the small village of Wollerau as a global hedge fund center. It is located about
40 minutes by car and 55 minutes by train from Zurich Airport, but is right
behind the border of the Kanton Zurich in the Kanton Schwyz, where regulations
are more favorable for their business model (ETH Zurich Airports and Cities
et al. 2010). We will turn back to leapfrogging later to explore in detail the case of
Singapore. There are also substantial allocation effects due to enhanced landside
accessibility – the airport shopping malls in Zurich and Amsterdam profit from
the landside transit hub. However, this is not an airport-specific phenomenon,
and we therefore do not regard it as a direct, but as an indirect effect resulting
from enhanced people flows. For smaller airports, allocation effects can also be
negative in cases where the local markets can be served from other regions due
to better accessibility (Whitelegg 2003).

266 Christian Salewski et al
Urbanization effects describe the creation of housing and other urban ser-
vices that are the result of new workplaces at the airport and workplaces created
because of greater global competitiveness. Allocation effects can be regarded as
a small segment of urbanization effects. Urbanization effects take place within
the daily urban region around a workplace, and they are by their very nature
very similar to effects of overall urbanization of the city region. The airport
itself is already a major workplace; about 64,000 people work at the airport in
Schiphol, about 25,000 in Kloten, and about 32,000 in Changi (Schiphol Group
2013; Flughafen Zürich 2013; Changi Airport Group 2013). These people live in
commuting distance to the airport. Due to shift work, commuting is mostly by
car, even though airport operators want to increase the use of public transport in
light of limited parking space. Commuting times can vary substantially depend-
ing on the specific case. Global and historical studies have found an average
commuting time of around one hour per day, with great differences in geo-
graphic distance and distribution depending on the mode of transportation, its
speed, and the form of its network (Schafer 2000; Marchetti 1994). However,
the total area affected by urbanization effects is much larger than commuting
distance to the airport. It extends beyond the airport region and is defined by
daily commuting times to and from the workplaces within it that were the result
Figure 13.6 eciffo tsoO tsrohnekueB eht ni sgnidliub eciffo eulav-dim ,ytisned-woL
park south-west of the airport, which lies inside the area in which housing is
forbidden
Source: Authors’ research.

Towards a model for airports and cities 267
of direct allocation effects. It covers an area up to about three hours plus about
30 minutes commuting time from the airport. These are overlapping daily urban
regions, each of which has a center – the workplace – within the catchment area.
We propose to use the term airport mega-city region in accordance with the
Polynet definition of mega-city regions (Hall and Pain 2006). An important
effect of urbanization within the airport area and around the noise contour can
be limitations to aviation as well as to landside transport capacity and hence
accessibility of the airport. This is the case in Zurich, where urbanization is
growing much faster than aviation.
At first glance, the resulting area typology suggests a concentric pattern of
effects of an airport (see Table 13.3).
However, these areas only describe the geographic possibility of the occur-
rence of substantial effects and not a homogeneous distribution. Within these
areas, effects are very unevenly distributed and can overlay areas. As a conse-
quence, it is necessary to further differentiate area types on a smaller scale.
The airport front side in Amsterdam and Zurich
The urban structures of the two cases Zurich and Amsterdam reveal some simi-
larities. In both cases, there are quite differentiated urban conditions within their
respective urban airport areas. The most important distinctions are related to the
geographic orientation to the airport terminal and the mother city. Amsterdam
and Zurich have hub status and have landside transit hubs, and they are among
the airports in Europe that have the longest history of operating at their current
location. In both cases, we could distinguish between two major conditions: the
airport front side and the airport backyard.
The term “airport front side” describes the urban conditions in the urban air-
port area between the airport and the mother city (see Figure 13.7).
Table 13.3 Effect types and affected areas
Effect type Possible affected area Typical distance to airport
Territorial effects Airport area (airport territory
and airport periphery)
0–~4 km
Aviation effects Noise landscape, noise
contour inversion
0–~10 km
Flows effects On all scales 0–Several hundreds km
Allocation effects Airport region
(catchment area)
Up to 3 hours commuting
ycneuqerf eht no gnidneped
of air travel
Urbanization effects Airport mega-city region
nabru yliad gnippalrevO(
regions of the catchment
area)
Up to 3 hours plus
gnitummoc setunim 03~
depending on local
commuting patterns
Source: Authors’ own.

268 Christian Salewski et al
This is a broad zone crossed by the high-capacity landside routes that connect
the terminal with the first sub-center of the mother city. At the terminal, and
within its walking distance, accessibility and connectivity is highest and mixed
use programs are located. This is the point of highest centrality in the urban air-
port area, and therefore the point of highest value for real estate development – a
peak of allocation effects and flow effects, as described in the airport city model.
The airports of Amsterdam and Zurich are centrally placed their city regions and
have consequently evolved into urban nodes. Non-aviation, landside transfer pas-
senger numbers in Zurich are now higher than for aviation, while Schiphol is an
important national railway node. On the side of the mother city, the first sub-
center towards the airport is the last stop before the airport – a term by the Dutch
urban designer, Kees Christiaanse – because heavy rail connections do not stop
between here and the airport. In Amsterdam, it is the South Station, in Zurich,
Oerlikon Station. The respective urban quarters, Amsterdam Zuid and Zurich
Oerlikon, are both important urban nodes in the city region, locations for
advanced services, hotels, and, in the case of Zurich, shopping. In Zurich, the
convention center is also located in Oerlikon, while in Amsterdam it is one stop
further at Amsterdam RAI.
Between the terminal and the last stop before the airport, the front sides in
Amsterdam and Zurich are affected by strong territorial compression and high
Figure 13.7 Amsterdam urban airport area, front side
Source: Authors’ research.
Notes: Front side between (1) airport city and (2) Zuidas station, the last stop before the airport.
In-between, compartmentalization by heavy infrastructure into urban enclaves such as (3) long-term
parking C3, (4) leisure area Nieuwe Meer, (5) Schiphol golf course, (6) Riekepolder business park.

Towards a model for airports and cities 269
compartmentalization. Urbanization pressure from both the airport and the city
affect a limited space due to one of the airport’s territorial effects: a further
expansion of the city is blocked by the airfield. The form of the transport network
is also affected by territorial and flow effects, as the front side is crossed by two
kinds of major transport infrastructure of two kinds: first, access roads and rail-
ways for the airport and, second, bypass and ring roads around the city and
around the airport. Viewed from the perspective of the urban center or the air-
port, respectively, the front side has traditionally had the status of a peripheral
border zone where large-scale, low-density overspill programs were located,
such as waste water treatment plants and a garbage incinerator in Zurich. Long-
term parking, family gardens, low-value light industrial zones, sports facilities,
and recreational zones can be found in Zurich as in Amsterdam. Both airports
have excellent public transport connections to the mother city and some of its
sub-centers, but high-capacity access systems for the airport bypass the front
side, leading to low local and partly low regional accessibility – in Zurich, the
S-Bahn serves some parts of the front side well, but does not always connect to
the airport. Territorial effects of the airfield, large-scale programs, aviation
effects, and landside infrastructure lines lead to a compartmentalization or phys-
ical fragmentation of the front side into urban enclaves. The airport front sides in
Amsterdam and Zurich are essentially conglomerates of disconnected heteroge-
neous elements and areas (see Table 13.4).
The airport corridor in Zurich and Amsterdam
Maurits Schaafsma and Mathis Güller’s conceptual city model airport corridor
suggests a linear development of high centrality and high-value programs through
the front side between the airport terminal and the last stop before the airport
(Schaafsma et al. 2008). Constant urbanization pressure has indeed led to
an increasing densification of the front side with mid- to high-value programs
such as the Glattpark housing and business park and hotels in Zurich, or
Riekepolder business park in Amsterdam. These developments are for the most
Table 13.4 Urban conditions at the airport front side
1 Compression through urbanization pressure from both airport and city center on
limited area (territorial effect)
2 Fragmentation by airfield, noise contour, and landside infrastructure lines (territorial
effect, flows effect)
3 Highest value at point of highest centrality at the terminal (flows effect, allocation
effect)
4 Great value differences in close geographic proximity (flows effect, aviation effect,
territorial effect)
5 Low local, high regional accessibility and connectivity (territorial effect, flows effect)
6 Grand development visions (in expectance of allocation effects)
Source: Authors’ own.

270 Christian Salewski et al
part not the result of allocation effects. Instead, locational choices were deter-
mined by good regional accessibility and connectivity, mainly by car. Not least,
the areas were partly affected by aviation effects and therefore land and real
estate was cheaper than in other locations of equal accessibility in the region
(Salewski and Michaeli 2012). Mid- to high-value programs in the airport cor-
ridor thereby emerged as an effect of overall regional growth, good regional
accessibility, and available and affordable land. Resulting are singular develop-
ments scattered between housing estates, old industrial areas, infrastructure
lines, and large-scale facilities with poor local accessibility and lack of public
transport, and therefore hardly a corridor.
Over the last years, accessibility and connectedness of urban areas in the cor-
ridor improved significantly. Due to the increasing density of workplaces, and
due to the increasing congestion of the road network, demand for public transport
increased, notably for office employees. Since 2008, the new Glattalbahn light
railway connects most of these development pockets with the terminal and
Oerlikon. The project has factually established the notion of an airport corridor
for the first time by stitching together previous enclaves and islands. It is only
now that spatial planning and policy is beginning to think about it as a corridor
at all – a first test planning procedure is currently in progress, and a second light
railway line through the front side is considered.
In the case of Amsterdam, the airport corridor has been drawn in a number of
policy documents (Schiphol Group 2007; Bestuursforum Schiphol 2012). In
some of them, the corridor extends beyond the airport and includes parts of
Hoofddorp and the Kruisweg. As in Zurich, the area between South Station and
the terminal has seen the development of office parks and hotels. Just as in
Zurich, these are unconnected enclaves, often separated by heavy infrastructure
lines and bordering other functional pockets – housing, recreation, sports, indus-
try, and facilities (see Figure 13.7). A local bus line runs from the terminal to
Amsterdam South Station, but its capacity and frequency is low, distances are
much greater than in Zurich, and densities are much lower. Another important
difference is the location of the terminal, which is surrounded by the airfield and
therefore not directly connected to the urban structure – its centrality can there-
fore not have a direct impact on the front side. The highway interchange and the
ring canal of Haarlemmermeer set further borders that are difficult to overcome.
However, urbanization pressure in Amsterdam metropolitan region remains high
even in times of crisis, and the front side has a high regional accessibility by car.
If an airport corridor can be formed, it will need a public transport project similar
to the Glattalbahn, a design strategy to deal with spatial borders, and a structure
that better connects it with Amsterdam Zuid and West.
The airport backyard and the airport tangent in
Amsterdam and Zurich
Outside the front side, the airport backyard describes the urban conditions for the
urban airport area that is not located between the airport and the mother city4

Towards a model for airports and cities 271
(see Table 13.5). In the backyard, there are no grand development visions.
Territorial planning is regarded as a task of the local municipality and the airport
operator. Typical programs are large-scale logistics, such as the strip bordering
the Kruisweg in Amsterdam, and support functions for aviation, such as parking
and cargo, which can be found mainly in Schiphol East and to the north-west at
long-term parking C3, or Im Rohr, west of Zurich Airport.
Another example lies in the north-west of Zurich Airport, where a long stretch
of military training grounds borders the fence. The backyard has above all much
more free, undeveloped land, much of which is in agricultural use and affected
by aviation effects under the noise contour. There is regional urbanization pres-
sure, as can be seen in housing developments in places like Bachenbülach north
of Zurich Airport, but less than in the front side. Landside infrastructure lines
also lead to compartmentalization, albeit with a larger mesh size due to the lack
of any notable territorial compression effect. The distortion of the urban struc-
ture through the airfield leads to a peripheral location “behind” the airport in a
car-based, low-density urban structure as in Hoofddorp, southwest of Schiphol,
or the northern Glattal north of Zurich Airport. An important territorial effect is
that major roads and rail lines are diverted to run along the airfield, such as the
highways A4 and A5 in Amsterdam or the Unterland highway in Zurich. In
Amsterdam, these conditions have led to the emergence of a development corri-
dor along the Kruisweg, which passes by the airfield on its south-west and does
not connect to the terminal or the mother city. We have termed this phenomenon
the airport tangent (see Figures 13.8 and 13.9).
With the establishment of the rapid bus transit line, the South Tangent 300/310
(the name describes its course tangential to the City of Amsterdam, not
Amsterdam Airport), the airport tangent is now partly connected to the terminal
and well-served by public transport.
Along it, major urban developments are projected, notably the logistics parks
A4 Zone West, with a high-speed train freight terminal, and Schiphol Logistics
Park. Recently, the main traffic flow has been rerouted to the new N201, a high-
capacity road that meanders around Kruisweg, thereby significantly broadening
the development corridor along the airport tangent (see Figure 13.10).
Table 13.5 Urban conditions in the airport backyard
1 Less urbanization pressure than in the front side, but still regionally high
2 Fragmentation by airfield, noise contour, and landside infrastructure lines, mesh size
larger than in the front side (territorial and flows effects)
3 No centralities
4 Low-density urban structure, low- to mid-value programs
5 Landscape and agriculture are under pressure, but some parts of it will remain
permanently due to security restrictions to building (aviation effects)
6 Not subject of attention for grand development visions, but regarded as large-scale,
open expansion space for airport operations and logistics
Source: Authors’ own.

Figure 13.8 aera scitsigol keoH eD eht hguorht gnissap enilsub dipar tnegnatdiuZ ehT
south of Schiphol
Source: Authors’ research.
Figure 13.9 Amsterdam urban airport area
Source: Authors’ research.
Notes: Airport tangent between (3) Hoofddorp center and (4) Aalsmeer center along (1) Kruisweg and
(2) N201 high-capacity road that “wriggles around” along a development corridor with areas such as
(5) Greenport Aalsmeer, (6) Schiphol Rijk business and logistics park, (7) Schiphol logistics park, and
(8) A4 Zone West logistics park.

Towards a model for airports and cities 273
In the cases of Zurich and Amsterdam, the urban airport area shows markedly
different conditions on the front side and in the backyard, even if they share
many effects. For the front side, the conceptual city models, airport city and air-
port corridor, are based on the idea of centrality. Kasarda’s aerotropolis also
describes a principally concentrical development around the terminal in line with
the conceptual city model that Burgess once developed for Chicago. The aero-
tropolis also quite literally follows Von Thünen’s concentrical spatial-economic
allocation model for cities, and is likely influenced by Walter Christaller’s Theory
of Central Places. Our findings challenge such concepts: Amsterdam and Zurich
display no concentric development, but a strong differentiation depending on
orientation of the urban airport area. For the backyard, non-centralized descrip-
tive city models like Thomas Sievert’s Zwischenstadt or Peter Rowe’s middle
landscape are more adequate. They also imply quite different approaches to reading
the area and consequently influence the character of interventions (see Table 13.6).
The controlled urban airport area of Singapore
The case of Singapore Changi Airport, a major Asian hub in a densely built-up
city, shows quite different urban conditions resulting from the airport’s effects
on the built environment.5 Changi is obviously located in a different part of the
world, but Singapore’s singular geographical and political structure – island and
Figure 13.10 The newly constructed N201 highway, view towards Hoofddorp train station
Source: Authors’ research.

274 Christian Salewski et al
city-state – also greatly contributes to Changi’s particular impact on the built
environment when compared to European airports. As Singapore’s largest air-
port by far, Changi is located on the eastern tip of the island, which makes it a
remote location and therefore a terminus stop for airplanes rather than a multi-
modal transport hub. A number of airport-related business clusters are located on
the western periphery of the airport, such as Changi North Business Park, the
Singapore Expo, and Loyang Industrial Estate. These may be considered to be on
the airport front side, located between Changi and the city center. As the airport
is at the shoreline, there is no backyard except for an area reserved for future
expansion. Yet Changi’s front side does not show similar conditions to Zurich or
Amsterdam. Its areas are mainly mono-functional and either aviation or business
related. Major transport infrastructures are present but not in larger density com-
pared to the rest of the island. These zones are rather poorly connected by public
transport to the nearby airport or neighboring districts. The centralized and
heavily planned political decision making structure of Singapore also largely
influences Changi’s impact on the island’s urbanization. If urban pressure due to
size concerns affects most of the island, the periphery of Changi is as much as
possible planned to enable future airport expansion and infrastructure accessibil-
ity. Therefore, other airports areas, such as Seletar Airport Aerospace Business
Park, are being planned for non-runway aviation related activities, while urbani-
zation pressure on the periphery of Changi is purposely kept to a minimum.
Leapfrogging allocation effects in the Singapore–Johor–Riau
cross-border region
While urban development is strictly controlled in Singapore, Changi Airport has
had significant allocation effects in its hinterland. For political and geographical
reasons, these can be found less in the airport area than on a much larger territo-
rial scale throughout the airport region – the Singapore–Johor–Riau (SiJoRi)
Table 13.6 Comparison of urban conditions of airport front side and airport backyard
Front side Backyard
Normative city model Airport city aerotropolis
airport corridor
?
Conceptual city model Burgess Von Thünen
Edge City
Zwischenstadt Middle
landscape
Density Rather built-up Still a lot of open space
Accessibility Mostly excellent Often poor
Compartmentalization Very high High
Programs High value
Mid value
Mid value
Low value
Urbanization Very fast Substantial but little noticed
Identity Center of airport area ? (Out of sight)
Source: Authors’ own.

Towards a model for airports and cities 275
cross-border region. The Malaysian state of Johor, immediately to Singapore’s
north, and the Riau Islands Province in Indonesia, just south of the island, have
seen Singaporean investments since the 1970s. Due to growing land and labor
costs, Singapore’s economic development strategy has led to the relocation of
manufacturing industries, land- and labor-intensive activities in these neighbor-
ing territories. Across this larger urban region, networks between Changi, sec-
ondary airports, local logistic firms, and small-scale transport infrastructures
enable the cross-border circulation of goods and people and integrate them with
the global infrastructure. Examples for allocation effects that leapfrog geo-
graphic and administrative boundaries can be found in two cases of producers of
fresh cut flowers and ornamental fish located in the state of Johor in Malaysia,
and in the case of electronic production on the island of Batam (see Figure 13.11).
These time-sensitive export goods rely heavily on air-transport, and perisha-
bles are part of the top 10 commodities of Changi Cargo.
The first case is Qian Hu Corporation, an ornamental fish farm and exporter
located in Sungei Tengha Agrotechnology Park on a 6.2-hectare leased plot
Figure 13.11 Singapore airport region with leapfrog allocation effects
Source: ETH Zurich Airports and Cities; FCL Singapore; Gasco 2013.
Notes: SIJORI cross-border region with three cases: (2) Qian Hu Corporation Head Quarter fish farm
in Singapore Sungei Tengha Agrotechnology Park with farms in (6) Batu Pahat and linked independent
growers in (3) Kota Tinggi, (4) Ulu Tiram, and (5) Simpang Ringan; (1) Hock Wee Nurseries parent
company in Singapore Lim Chu Kang Agrotechnology Park with main farm in (3) Kota Tinggi and
farms in (9) Sungai Tiram, (10) Nam Hang, (13) Bandar Tenggara, and linked independent growers in
(4) Ulu Tiram, (7) Kulai, and (8) Ban Foo; (11) Batamindo Industrial Park with electronic multina-
tional cooperations, with (14) Electronic MNC HQ and final test center in Singapore Kallang Area,
and (15) Electronic MNC Distribution Center Asia in Bedok North near Changi Airport.

276 Christian Salewski et al
and employing around 150 people. Their headquarters are in Singapore, with
affiliations in Malaysia, Thailand, and China. The ornamental fish are imported
on a daily basis from all over the world through Changi Airport or collected from
local breeders mainly located in areas in the state of Johor. Once flown and
trucked to Qian Hu in Singapore, the fish are quarantined, bred, packed, labeled
“from Singapore” and flown back from Changi Airport to customers all around
the world. The second case is Hock Wee Nurseries, a Singaporean orchid grower
located in the state of Johor. The parent company is located in Singapore on a
2-hectare leased plot in the Lim Chu Kang Agrotechnology Park, but it owns four
farms totaling 205 hectares of land and employs 625 people in Malaysia. Around
70 independent growers located all around the state of Johor deliver f lowers to
the main farm of Tai Hong, located 75 km away from Changi Airport. Every day,
three to six trucks cross the border between Malaysia and Singapore to reach
Changi Airport. Every single day, Hock Wee Nurseries exports around 1,500 to
2,000 parcels or 500,000 flowers around the globe via Changi Airport.
The third case is the presence of multinational corporations in electronics that
operate their production sites from industrial parks in free trades zones located
in Batam in the Riau. Batamindo Industrial Park pioneered the development of
these industrial estates. Nested on 305 hectares of land, 60,000 employees work
in over 70 multinational manufacturers such as Philips, Siemens, Sanyo,
Schneider Electric, or Infineon. Batamindo Industrial Park is managed by
Gallant Venture, a joint enterprise between Indonesian and Singaporean contrac-
tual partners. The Park leverages on Singapore’s reputation for management,
technical expertise, global infrastructures, and proven legal system, on one hand,
and on Batam’s cheap labor and affordable land resources on the other. Its location
in a free trade zone saves its companies import, value-added, and exports taxes
while being right across a financial hub with high-class worldwide connections
through Changi and the Singapore port. Batamindo Industrial Park is master-
planned as a self-sufficient infrastructure. It is located in the heart of the island
among tropical greenery and surrounded by a well-guarded fence. The Park is
located 15 minutes away from Batu Ampar cargo port and Hang Nadim Airport,
and efficiently connected to them by excellent road infrastructures. The enclave
is accessible through five gates, of which only two are opened to the public until
midnight while the others are used by logistics companies and workers who are
free to navigate in and out of the estate as they please. Inside, the park contains
its own neat tree-lined roads and mini-bus system, its own power and water treat-
ment plant, a telecommunication tower, around 2,800 dormitories for migrant
workers, and a small commercial town center with shops, food center, places of
worship, and banking facilities. In its “Singapore-like” self-organized system,
Batamindo functions fairly independently from the rest of the island of Batam.
The main items produced in the compound are high-value electronic microchips.
Due to their size, high price, but also production process, the microchips involve
air traffic logistics, from the components delivery for assembly in Batam to the
finished product exportation. Every day, four propellers flights are organized
between Hang Nadim’s Batam Airport and Seletar, Singapore’s airport for

Towards a model for airports and cities 277
smaller-body aircrafts. Once the goods reach Seletar, a local logistics firm trans-
ports the bounded transshipment to Changi for global exportation.
These flows of time-sensitive and high-value commodities depend on net-
works of small-scale transport systems and secondary airports to transport them
tax-free to Changi. The small and medium agro-technological enterprises and
the multinational electronics cooperations strongly depend on Changi, yet they
are not located in its airport area but across the national borders where land and
labor are available and cheaper. Good landside accessibility and connectivity
ensure that they remain within the catchment area of Changi. Through these
processes, the presence of Changi shapes and supports an intricate system of
urban fabric throughout the region of Singapore and its hinterland.
Towards an effect-based model for airports and cities
The three cases show that the proposed five effects of airports on the built
environment – territorial effects, aviation effects, flows effects, allocation
effects, and urbanization effects – do not lead to the same type of urban areas.
Besides both being located in north-western Europe, Amsterdam and Zurich
might share some similarities not least due to the fact that they are very old air-
ports that did not move out when urbanization came closer: Schiphol is “city-
locked” within the Randstad, Kloten caught between urban, territorial, and
topographical limits. The case of the seaside location of Changi illustrates not
only that geography may be as important as the distance to the mother city, but
also that urbanization in airport areas can be controlled to such an extent that
hardly any effects on the built form appear. However, the leapfrog effects in its
hinterland give us an idea that, even in Singapore, some effects do have an influ-
ence on urban structure after all, even if it is beyond the national border. All three
cases suggest that the five effects do not form the built environment in a like
manner around airports, as is suggested in the concentric aerotropolis model, nor
into a linear city of the airport corridor. Instead, they can have substantial impact
on urbanization patterns that are specific to each city region; the airport does not
form, but alters the shape of the city and the landscape. In an ongoing process of
urban mutation, the airport is a relevant force, but only one of many.
Further research into airport-specific urbanization patterns is necessary, both on
smaller scales and for more cases. Such an investigation should lead to a catalogue of
effect-related area types and possible combinations thereof that can be used to com-
pare specific airports and their city regions. The second task is to reduce the current
knowledge gap between economic models and city models. This is particularly
important to improve the debates about benefits and disadvantages of airports for
city regions. In the long term, a future effect-based model of airports and cities
needs to go further than looking at the urban structure alone. Research on the effect
of airports on transport, energy, waste and water flows, governance and economics,
sociology and culture, ecology, and landscape would ideally be part of such a model.
As the respective disciplines are already researching and simulating the influence of
the airport, at least some partial integrations seem feasible at the moment.

278 Christian Salewski et al
Practical and scientific challenges notwithstanding, and based on our findings
in Amsterdam, Zurich, and Singapore, we are inclined to conduct further research
on three specific possible elements of integration. For one, the improvement of
public space and landscape in the airport area may help to qualify areas disad-
vantaged by fragmentation, compression, and noise. A second element is transit-
oriented, mixed use and dense urban nodes connected by high-capacity public
transport that might eventually form a real and more sustainable airport corridor.
The third idea concerns the airport itself. In Amsterdam and Zurich, the airport
is already developing into an urban node and thereby serves not only aviation, but
also its area and its region. However, the airport as an urban node has great
potential in becoming more than an airport city, a concept that basically describes
a transit hub with shopping mall and offices. The airport may become a public
realm with public space and mixed program, and its noise landscape could
develop into a special regional open space for ecological services and leisure.
Such an airport may eventually embody the identity of its region and become the
true center of its urban airport area (see Figure 13.12).
Notes
1 Evidence for airport-relatedness of enterprises located in the airport area is scarce. For
Amsterdam, studies by Warffemius et al. (2008) showed that 40 percent of European
distribution centers close to Schiphol were not airport-related. Yet, Van Wijk et al.
Figure 13.12 Conceptual models for airports and cities
Source: Authors’ research.
Notes: (1) airport as infrastructure, (2) airport city and aerotropolis, (3) airport as urban node in the
airport region.

Towards a model for airports and cities 279
(2011) observed that in areas developed by Schiphol Area Development Company
SADC, active policy led to about 80 percent airport-relatedness of companies in com-
parison to about 45 percent elsewhere. However, the testing criteria applied for SADC’s
policy and the research may be considered to be rather broad. For an overview of the
spatial-economic development of Schiphol regions during the twentieth century, see the
recent publication by El Makhloufi (2012).
2 Mark Michaeli proposed to use the term “Raumbeugung” (spatial distortion) for this
phenomenon.
3 We take this estimate from the ESPON study Airports as Drivers of Economic Success
in Peripheral Regions (ESPON et al. 2012) on the economic impact of small airports,
which found effects of new airports only in cases where the next existing airport was
further away than three hours commuting. We regard a 3-hour commute, therefore, as a
maximum distance for notable allocation effects.
4 The term “airport back yard” poses a number of problems due to its negative associations.
Initially, we aimed at distinguishing the geographical orientation of the airport and its main
terminal in respect to the mother city. We considered, but eventually discarded, alternatives
such as rear side, far side, or back. However, the term “back yard” is certainly appropriate
in many respects; in the airport back yard, much development has taken place without
integrated planning and consideration for long-term quality, not least because the area was
out of sight for many decision makers concentrated on the front side. Metaphorically
speaking, the airport is also in many ways responsible for, and dependent on, the develop-
ment in its back yard. Once a sustainable transformation of the airport backyard and the
noise landscape is successful, we may think about calling it an airport back garden instead.
5 The case of Changi is based on original research in progress by Anna Gasco, ETH
Zurich/Future Cities Laboratory Singapore (Gasco 2013).
6 This chapter is an outcome of three research projects of the Airports and Cities Research
Platform, ETH Zurich Chair for Architecture and Urban Design, Prof Kees Christiaanse:
the Better Airport Regions research project (sponsored by NWO, Nicis, VerDuS, URD);
Module IV of the ETH Future Cities Laboratory Singapore (sponsored by SEC); and the
Urban Resources module of the National Research Program 65: Urban Quality (spon-
sored by SNF).
References
ACI Europe (1998) Creating Employment and Prosperity in Europe. Brussels: Airport
Council International – European Region.
Bestuursforum Schiphol (2012) Ontwikkelingsstrategie 2012 van de Ruimtelijk
Economische Visie Schipholregio. Schiphol: Bestuursforum Schiphol, 26.
Bosma, K. and Nikolaeva, A. (2013) “The Airport: Prototype of the Global City?,” in
Berkers, M. et al. Schiphol Megastructure: Design in Spectacular Simplicity. Rotterdam:
nai010.
Changi Airport Group (2013) Facts & Statistics – Changi Airport. Available at: http://
www.changiairport.com/our-business/about-changi-airport/facts-statistics (accessed June
30, 2013).
El Makhloufi, A. (2012) Spatial-Economic Metamorphosis of a Nebula City: Schiphol and
the Schiphol Region During the 20th Century. New York: Routledge.
ESPON and Department of Sciences for Architecture (DSA), University of Genoa (2012)
“ADES–Airports as Drivers of Economic Success in Peripheral Regions, Targeted
Analysis 2013/2/17,” (Draft) Final Report | Version 1 30/11/2012. Available at: http://
espon.eu/main/Menu_Projects/Menu_TargetedAnalyses/ades.html (accessed June 22,
2013).

280 Christian Salewski et al
ETH Zurich Airports and Cities, Schenkel, Isabelle and Stocker, Lea (2010) Ein Atlas
Europäischer Flughafen und Städte. Zurich: ETH Zurich, Chair for Architecture and
Urban Design, Prof Kees Christiaanse.
ETH Zurich Chair for Architecture and Urban Design, Christiaanse, K., Kiss, D.,
Kretschmann, N., Kretz, S., and Wagner, M. (2010) Seedamm I: Urban Design Studio
Herbst 2010. Zurich: ETH Zurich.
Flughafen Zürich (2013) Zahlen und Fakten 2012. Zürich: Flughafen Zürich.
Freestone, R. and D. Baker (2011) “Spatial Planning Models of Airport-Driven Urban
Development,” Journal of Planning Literature 26(3): 263–79.
Garreau, J. (1991) Edge City: Life on the New Frontier. New York: Doubleday.
Gasco, A. (2013) “Flying Fish & Chips: The Urban Infrastructure of Singapore Airport.”
PhD thesis, supervised by Prof Kees Christiaanse, Singapore: TH Zurich/Future Cities
Laboratory.
Geldermans, B., Wandl, A., and Van den Dobbelsteen, A. (forthcoming) Strategies For
Essential Resource Flows and Their Infrastructures in Airport Regions – The Case of
Amsterdam Airport Schiphol.
Güller, M. and Güller, M. (2003) From Airport to Airport City. Barcelona: Editorial
Gustavo Gili.
Hall, P. and Pain, K. (2006) The Polycentric Metropolis: Learning from Mega-City Regions
in Europe. London; Sterling, VA: Earthscan.
Häne, S. (2012) “Der Flughafen hat mehr ÖV-Reisende als der Bahnhof Genf ’, in
Tagesanzeiger, 20.03.” Available at; http://www.tagesanzeiger.ch/zuerich/region/
Der-Flughafen-hat-mehr-OeVReisende-als-der-Bahnhof-Genf/story/20736814 (accessed
June 22, 2013).
Hubstart Paris (2011) “Sustainable Airport Area International Seminar, Shaping the 21st
Century Model For Airport Regions, Paris-Charles de Gaulle, 21–22 November 2011,
proceedings.” Available at: http://hubstart-paris.com (accessed June 22, 2013).
Lindsay, G. and Kasarda, J. D. (2011) Aerotropolis. The Way We’ll Live Next. London:
Allen Lane.
Lynch, K. (1981) A Theory of Good City Form. Cambridge, MA, and London: MIT Press.
Marchetti, C (1994) “Anthropological Invariants in Travel Behavior.” Technological
Forecasting and Social Change 47(1): 75–88.
Municipality of Haarlemmermeer (2013) “Park 21, A New, Metropolitan Park in the
Amsterdam Metropolitan Area.” Available at: http://park21.info (accessed June 22,
2013).
Orth, H. and Weidmann. U. (forthcoming) Airport Cities and Airport Ground Access –
Demand Balancing or Peak Exacerbation? Zurich: ETH Zurich Institute for Transport
Planning and Systems.
Salewski, C., Boucsein, B., Christiaanse, K., Michaeli, M., Schaafsma, M. (2011) “Urban
Regional Integration: Improving The Carbon Balance Of Airports And Cities,” White
Paper for the Climate-KIC conference Airports as Low-Carbon Cities, Schiphol the
Grounds, Amsterdam 2012.
Salewski, C. and Michaeli, M. (2012), “Zürich Airport Corridor Toevallig Onstaan,”
Stedenbouw en Ruimtelijke Ordening S+RO: 6.
Schaafsma, M., Amkreutz, J., and Güller, M. (2008) Airport and City. Airport Corridors:
Drivers of Economic Development. Amsterdam: Schiphol Real Estate.
Schafer, A. (2000) “Regularities in Travel Demand: An International Perspective,” Journal
of Transportation and Statistics 12: 1–31.

Towards a model for airports and cities 281
Schiphol Group (2007) Ruimtelijk Ontwikkelingsplan Schiphol 2015. Schiphol: Schiphol
Group, 15.
Schiphol Group (2013) “Schiphol–Sustainable Employment.” Available at: http://schiphol.
nl/SchipholGroup/CorporateResponsibility1/SustainableEmployment.htm (accessed June
30, 2013).
Sieverts, T. (1997) Zwischenstadt – zwischen Ort und Welt, Raum und Zeit, Stadt und
Land. Braunschweig [etc.]: Vieweg.
Van Wijk, M., Brattinga, K., and Bontje, M.A. (2011) “Exploit or Protect Airport Regions
From Urbanization? Assessment of Land-Use Restrictions in Amsterdam-Schiphol,”
European Planning Studies 19(2): 261–77.
Warffemius, P., Van der Hoorn, T., and Klaassen, H. (2008) “The Dynamic Spatial Impact
of Amsterdam Airport Schiphol,” Aerlines 42: 1–4.
Whitelegg, J. (2003) The Economics Of Aviation: A North-West England Perspective,
Program-Based Conceptual Models for Airports and Cities. Lancaster: CPRE North
West Regional Group.