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IOP Conference Series: Earth and Environmental Science
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A systematic review of motives for densification in Swedish planning
practice
To cite this article: P A Haupt et al 2020 IOP Conf. Ser.: Earth Environ. Sci. 588 052030
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BEYOND 2020 – World Sustainable Built Environment conference
IOP Conf. Series: Earth and Environmental Science 588 (2020) 052030
IOP Publishing
doi:10.1088/1755-1315/588/5/052030
1
A systematic review of motives for densification in Swedish
planning practice
P A Haupt1, M Y Berghauser Pont2, V Alstäde2 and P G Berg3
1 Blekinge Institute of Technology, Department of Spatial Planning, Karlskrona
Sweden, per.haupt@bth.se
2 Chalmers University of Technology, Department of Architecture and Civil
Engineering, Gothenburg Sweden
3 SLU Landscape, Ultuna, Department of Urban and Rural Development, Uppsala
Sweden
Abstract. One of the current dominant strategies proposed for sustainable urban development is
densification. While some advocate the very reasonable benefits of density, others emphasize
the potential drawbacks. The main goal of this paper is to provide a systematic overview of
the claimed benefits of densification in Swedish practice and relate this to the scientific
evidence. For the systematic overview, comprehensive plans from 59 Swedish
municipalities, covering plans from both highly urbanized areas as well as more rural
regions, are included. The results show that in three out of four cases where density or
densification is mentioned, no motive is given. For the other quarter, the most often used
motivation is related to transport (19%), services (17%) and urban environmental
qualities (14%). The least frequent motives used are related to health (8%) and ecology
(2%). The motives in comprehensive plans are for the most part pointing to a positive impact of
density on sustainable urban development (77%), which is not always supported by the
empirical evidence that more often describe a negative correlation. Furthermore, many of
the most frequently used motives in comprehensive plans have little scientific support, which
puts new questions on the research agenda.
1. Introduction
Global urbanization is proceeding at an unprecedented rate [1], resulting in fierce competition between
land uses. The compact city approach has gained global impact as a planning approach since the 1990s
[2], which, through densification and compact building, provides several environmental gains,
especially related to the reduction of greenhouse gas emissions, innovation and proximity to service [3].
Density as a concept in urban planning and design was introduced in the second half of the nineteenth
century to control fires, disease and social disorder that was argued to be related to high densities in
industrializing cities [5]. As a result, planning controls were developed that prescribed maximum
densities, e.g. through building ordinances [6]. Today, high densities are judged by many to be the best
response to counter current problems such as climate change, land fragmentation and loss of
biodiversity. The UN-supported Millennium Ecosystem Assessment [7] and the American EPA [8]
argue for city compaction as an environmental benign strategy. Another example is UN Habitats [9]
recommended density of over 150 inhabitants per hectare to arrive at more sustainable urban
development. There seems to be consensus that sprawling cities, private mobility and high levels of
energy consumption go hand in hand [10]. Advantages of higher densities are better accessibility to
BEYOND 2020 – World Sustainable Built Environment conference
IOP Conf. Series: Earth and Environmental Science 588 (2020) 052030
IOP Publishing
doi:10.1088/1755-1315/588/5/052030
2
municipal service opportunities [11], public transport [6] and innovation and productivity [3]. However,
there are also negative effects associated with higher density such as well-being, social conflicts and
decreasing capacity to absorb rainfall. More recently, the negative correlation between biodiversity and
increased urban density has frequently been discussed [4].
This paper aims at providing an overview of motives for densification as expressed in Swedish urban
development policy documents, with a focus on comprehensive plans. The Swedish case is chosen
because it is often discussed as a showcase for sustainable urban development (with examples such as
Hammarby Sjöstad and Norra Djurgårdsstaden). Further, focusing on one country allows for comparison
of plans developed under comparable circumstances (reasonably common juridical, political and
cultural frameworks), but with varying population densities. The systematic review will give insight
in the arguments used most frequently and allow us to identify matches and mismatches between
contemporary Swedish planning practice and the state of research using a parallel systematic review
covering 330 scientific articles. The findings of this article review are discussed in detail in [12].
The objective of the current policy review is thus to map the arguments used for densification in
urban planning today and compare this to the scientific evidence found. The two main research questions
are: What are the main motives used for densification? and How do these match with evidence found in
research? The results are used to answer the overarching research question about which arguments are
used in relation to densification as a means to contribute to one of the sustainable development goals
(SDG) of the United Nations ´Sustainable cities and communities´ (SDG11). Furthermore, the mirroring
of these findings with the scientific evidence provides insight whether these arguments build on evidence
and, if not, whether arguments and strategies should be modified. We do not address SDG11 directly
but through arguments used for densification that can be related to other SDG such as good health and
well-being (SDG3), inequality (SDG10), climate change and its impacts (SDG13) and biodiversity
(SDG15).
The outline of the paper is as follows. In the next section, the method for the systematic review is
described. In the following section, the quantitative synthesis is discussed and results from the reading
of the comprehensive plans are mirrored in results from the article review. The last section discusses
these findings in relation to sustainable urban development by highlighting matches, mismatches and
ambiguities. This will be used to define recommendations for practice and an agenda for future research.
2. Method
For the systematic review of Swedish comprehensive plans, a representative sample of 59 plans from
the 290 municipalities in Sweden, is selected. 5 Comprehensive plans are politically established policy
documents that each municipality is obliged to have and needs to be evaluated, updated or revised once
every election term (every fourth year). The review includes comprehensive plans from 2000 to 2019
(of which 85% are less than ten years old). Further, because it is expected that density is a strategy more
often discussed in municipalities including larger cities and because these are much fewer in number,
all municipalities with more than 100.000 inhabitants are included. This includes the three largest
municipalities with more than 300.000 inhabitants (Stockholm, Gothenburg and Malmö) and thirteen
municipalities between 100.000 and 300.000 inhabitants. Of the 274 smaller municipalities (with less
than 100.000 inhabitants), a random selection of 43 municipalities is included in the final sample. The
results of the review are assessed using a priori defined questions. This allows for a systematic and
transparent assessment of the comprehensive plans that can be discussed with a high level of objectivity.
The following questions are used to systematically summarize the selected comprehensive plans:
1. How often is density mentioned (i.e. simple count)?
2. Which motives are used in relation to densification?
3. Is the expected outcome deemed to be positive or negative for sustainable urban development?
5 We planned to include 60 municipalities, but Örebro’s comprehensive plan (part of the random selection) was
excluded because the municipality has a digital plan with interactive maps, but no comprehensive text.
BEYOND 2020 – World Sustainable Built Environment conference
IOP Conf. Series: Earth and Environmental Science 588 (2020) 052030
IOP Publishing
doi:10.1088/1755-1315/588/5/052030
3
For the systematic review, we used the search function of Adobe Acrobat to find the keyword ´density´
as well as related terms such as ´dense´ and ´densification´ and some opposing term for dense such as
´sprawl´ and ´dispersed´.6 All hits are registered as simple counts and if a motive is mentioned in the
same sentence or paragraph that clearly links to density, this argument is noted. The motives are in a
next step categorized as having a positive or negative contribution to sustainable urban development. In
most cases this is rather straight forward such as preserving limited resources – a fundamental
sustainability principle - while it is more challenging in other areas such as economics where in cases
of a high level of ambiguity, the contribution is defined as neutral.7 The motive must have a clear
semantic relation to the keyword in order to be included in the analysis. The search does not include any
results from images, captions, maps, illustrations or headings. Besides an overview of motives used in
the comprehensive plans, we also discuss whether the degree of urbanization plays a role in the
arguments used. The hypothesis is that more urban municipalities more often highlight negative effects
of densification, while less urban municipalities argue more often that densification e.g. contributes to
better public finances and feasibility to maintain public services such as public transport.
3. Quantitative synthesis of results
The arguments identified in the reviewed comprehensive plans are grouped in nine categories (Table 1).
These categories are further divided into sub-categories. It should be noted that these categories are
designed based on the plans selected for the systematic review discussed in this paper and the parallel
review of scientific articles [13].
The first category, technical infrastructure, includes aspects related to capacity of e.g. water and
sewerage that changes when more housing units are added to an area. The tree other sub-categories are
surface water management, energy, and road and rail infrastructure. The second category, resource
efficiency, covers the effective use of existing natural and land resources. It should be noted that we here
only include the resource ´land´ in general terms and the resource ´natural areas including agricultural
land, nature and forests´. The more economically driven resource efficiency argument is found under
the category economics. The next main category is service, including the sub-categories accessibility to
service; the customer base of commercial and public service; presence and accessibility of recreational
green; and housing. The subsequent category economics includes three sub-categories: labor
productivity (including innovation and entrepreneurship), property values (including housing prices)
and public finances. Ecology includes three motives: biodiversity, mainly focusing on topics related to
species diversity; ecological quality, which relates to ecosystems and their stability over time; and
climate related issues in general. Urban environment is the category that groups all topics that describe
the spatial qualities of the built environment. It covers the following four sub-categories: mixed land
uses, cultural and esthetic qualities, micro-climate, and spatial qualities such as proximity. Transport is
the category with most sub-categories. We distinguish three different modalities (public transport,
pedestrian & bicycle, and car); sub-categories that relate to the use of these transport modes (car
ownership, trip distance, choice of modality, and general travel behavior); energy use related to
transport; and emissions related to transport. A last category is travel safety where especially traffic
accidents are in focus. The subsequent category is social impact. Here we distinguish issues related to
well-being, social interaction, social equity, and crime. The sub-category well-being or quality of life
focuses on the individual, while the sub-category social interaction concerns the meeting and interaction
between individuals. The last main category human health includes topics such as walkability and
obesity, and psychological health, including stress and problems related to for instance sleep. Noise and
air pollution are included as separate sub-categories as they represent the top two in disease burdens
among environmental factors in Europe [13].
6 Because the plans are written in Swedish, we use the Swedish keywords tät, förtätning, täthet, gles, hög
exploatering, låg exploitering.
7 An interpretation of the contribution to sustainable urban development has been made on basis of contemporary
mainstream discourse on sustainability.
BEYOND 2020 – World Sustainable Built Environment conference
IOP Conf. Series: Earth and Environmental Science 588 (2020) 052030
IOP Publishing
doi:10.1088/1755-1315/588/5/052030
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3.1. Results of the reading of 59 comprehensive plans
In the 59 comprehensive plans, the keyword density was used 3.298 times, whereof 905 times
accompanied with a motive (i.e. 27% of hits have a motive). Further, in more than three out of four cases
(77%) the used motives can be deemed as being in support of the argument that higher density
contributes to sustainable urban development. How often different motives are used is shown in Figure
1, depicting a rather balanced spread over the different main categories, except for ecology. The most
frequently used motives are transport related (19%), followed by service-related motives (17%) and
arguments that are more spatial in nature (urban environment; 14%). The least frequently used
arguments relate to health (8%), infrastructure (6%) and ecology (2%).
Figure 1. Distribution of the argued for relation between density and its outcome.
Despite the relatively even distribution in the main categories, a more diverse picture is found when
looking at all the sub-categories (Figure 2). For infrastructure, the sub-categories surface water
management and energy are the most frequently mentioned; all sub-categories related to resource
efficiency are discussed equally often; service-related arguments focus mainly on accessibility,
improved customer base and presence of and/or access to recreational green, while housing is least
discussed. The last one is noteworthy, because densification is most often a means to provide more
housing. However, this motive might seem too obvious to even be mentioned. When economics are
discussed, most of the arguments relate to public finances and labor productivity. Arguments related to
land and property values are largely absent. All sub-categories within ecology are discussed equally
often. When the urban environment or the spatial quality is discussed in relation to density, most
repeated motives concern cultural and aesthetic qualities and general spatial conditions such as
proximity. Arguments related to social factors most regularly address social interaction and crime, while
well-being and equity is less often referred to. Health arguments related to density are for the large
majority related to noise and air pollution. Transport related motives are in two third of the cases
belonging to the category sustainable modes of transport. The argument is that higher densities will
contribute to more people using public transport or choosing more active modes such as walking or
cycling.
The public transport motive is also the most frequently used of all sub-categories in this review,
always with a deemed positive contribution to sustainable development (Figure 3). The second most
frequently used argument is the role of density to create better spatial conditions in terms of general
proximity. Other motives in the top-20 are public finances and a good customer base for service as well
as social interaction. The motive of access to recreational green is relatively often used, but in 40% of
the cases as a negative effect of densification. Other stated negative effects of densification that are
frequently mentioned are noise, air pollution and problems related to surface water runoff.
BEYOND 2020 – World Sustainable Built Environment conference
IOP Conf. Series: Earth and Environmental Science 588 (2020) 052030
IOP Publishing
doi:10.1088/1755-1315/588/5/052030
5
c
Figure 2. Sub-categories of motives and their distribution within each main category.
Figure 3. Top-20 of used motives where the amount of positive effects on sustainable urban
development are depicted in green (positive values represent the number of registered hits) and negative
ones in yellow (minus values represent the number of registered hits).
3.2. Differences between municipalities
The difference between municipalities with more versus less than 100.000 inhabitants is minimal. After
dividing the sample in two, the groups are compared to the full set. No differences are found in the ratio
between total hits and hits with motives and almost the same percentage argues that higher density
contributes to sustainable urban development; 79% in the more populated municipalities compared to
BEYOND 2020 – World Sustainable Built Environment conference
IOP Conf. Series: Earth and Environmental Science 588 (2020) 052030
IOP Publishing
doi:10.1088/1755-1315/588/5/052030
6
76% in the less populated ones. In other words, the most populated municipalities do not have more, or
less, arguments for higher densities, neither can they be said to value densification differently than the
less populated municipalities. Regression analysis shows that population density and countryside quota
correlate with the frequency the keyword density is mentioned in the comprehensive plans (i.e. number
of hits), while the total number of inhabitants registered in a municipality is not significant. Population
density and countryside quota together explain 22% of the variation in the number of hits. In other
words, more urbanized populated municipalities use the keyword density more often in their
comprehensive plans. However, there is no difference between municipalities in how often a motive is
used in relation to density. To understand whether there are differences in the motives used, the overall
mean population density and the mean countryside quota is compared with the means within each
motive. The result shows that less urbanized municipalities more frequently use motives related to
cultural quality, public transport and customer base for service. The latter two are directly related to the
need for a certain population density to make service feasible while the first might concern the topic of
cultural heritage where an increase in density is seen as a threat to existing cultural and esthetic qualities.
For the more urbanized municipalities (with higher density and/or lower share of countryside), motives
more frequently used are related to land resource efficiency, access to recreational green and surface
water management. All three relate to the competition between land uses that become more severe when
densities are higher. The first motive might be related to safeguarding the scarce non-urbanized land,
while the second and third discuss the relation between green areas and other impervious land in the
already urbanized areas that, through more densification, decrease. We can thus conclude that density
is mentioned more often in more urbanized municipalities. Further, motives are used equally often, but
the type of motives used differs depending on the level of urbanization.
3.3. Mirroring the results of the policy review with the scientific review
Although the main focus of this paper is not to systematically compare the patterns in motives for
densification found in comprehensive plans in Sweden with scientific evidence found in international
peer reviewed journals, some first preliminary findings can be discussed. For a more extensive
discussion of the systematic review on empirical studies that relate density to various outcomes, see
[13]. First, the argued effects and studied outcomes of densification are not distributed in similar ways
(Figure 4).
Figure 4. Main categories where the amount of positive effects on sustainable urban development are
depicted in green (positive values represent the number of motive hits and papers respectively) and
negative ones in yellow (minus values represent the number of motive hits and papers respectively).
The distribution of motives in comprehensive plans is relatively even, while the scientific articles
primarily study transport related outcomes. This means that some motives used in planning are not well-
studied. Second, the arguments in comprehensive plans are for the most part positive, while the scientific
studies show a more diverse result. Density has empirically underpinned positive effects on transport
COMPREHENSIVE PLANS
SCIENTIFIC PAPERS
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IOP Conf. Series: Earth and Environmental Science 588 (2020) 052030
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doi:10.1088/1755-1315/588/5/052030
7
related outcomes and economics, but outcomes related to ecology, social impact and urban environment
are for the most part negative. This means that practice, when measured against the scientific results,
can be said to have an unbalanced bias towards a too large degree of claimed positive effects in
categories central to urban and spatial planning.
The comparison between the top-20 of sub-categories found in the comprehensive plans with the
evidence of density effects from scientific studies is striking. The comparison in figure 5 shows that
some motives are supported by empirical findings. Examples of these are the relation between density
and usage of sustainable modes of transport, public finances, air quality and surface water management.
However, some motives are deemed more positive than what the evidence supports (e.g. social
interaction, labor productivity, and crime), while others are too negative (e.g. recreational green). Most
striking, though, is that many of the motives lack sufficient scientific support. The most frequently
studied outcomes of density are in many cases not part of the top-20 motives in the comprehensive plans,
e.g. physical and psychological health, well-being, safety, biodiversity and ecological conditions, micro-
climate, and air quality. Moreover, the majority of the most frequently studied outcomes are negative
for sustainable urban development [12].
Figure 5. Top-20 of arguments used in comprehensive plans (in green) and outcomes studied in
scientific articles (in yellow). On the far right, the most frequent used arguments in the comprehensive
plans.
4. Conclusions and discussion
The review of comprehensive plans shows a large variation in motives related to density and
densification. Few differences are found between more urban municipalities and less densely populated
municipalities with more agricultural hinterland. The motives used differ slightly with, as expected,
more focus on motives related to feasibility in less urbanized municipalities and on motives related to
land resource efficiency, access to recreational green, and surface water management in more urbanized
municipalities. Most motives found in comprehensive plans can be categorized as positive for
sustainable urban development. When compared to the scientific evidence, some motives are supported,
but many frequently used motives lack empirical support. Furthermore, these frequently used motives
are often deemed more positive for sustainable urban development than can be scientifically supported.
On the other hand, the more frequently studied outcomes in the scientific papers are less often used
motives in comprehensive plans. Moreover, these scientific outcomes show for the most part a negative
relation between density and sustainable urban development. This is troublesome because, on the one
hand, motives are used where there is little scientific support (except for transport related motives); on
the other hand, sub-categories where more scientific research is at hand - which in some cases
demonstrate negative effects of densification - are the least addressed in comprehensive plans. Thus, it
can be said, comprehensive plans give a too positive view on densification as a means for sustainable
urban development.
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IOP Conf. Series: Earth and Environmental Science 588 (2020) 052030
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8
Acknowledgments
The project is funded by The Swedish Research Council Formas, nr 2018-00281, Density and
sustainability: norms in practice and the results of research.
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