Chapter

1

Cities andtransportation
Kenji Doi
Professor, Department of Global Architecture, Graduate School of Engineering, Osaka University

1.1

The dynamics of urbanization and the role of transportation

Cities change with the passage of time, moving from growth to decline. To make an analogy with human
life, cities pass from periods of childhood to adolescence (urbanization), young adulthood to middle age(suburbanization), and into old age (disurbanization). However, cities also expect a fourth phase notcomparable to human life, one of reurbanization.1) The form of urban transportation changes with thegrowth phase of the city, and the role of urban transportation changes as well according to the life cycleof the city as shown in Figure 1.
The role of transportation demanded in the urbanization phase is the carrying of large numbers ofpeople into the city, for example by railways. During suburbanization, the emphasis is on moving people
quickly over long distances. In the latter half of the suburbanization phase, the increasing developmentof low-density suburbs shifts the predominant modes of transportation toward private automobiles.
Later in the disurbanization phase, increased spread of low-density urban areas (urban sprawl) causes a
decline in public transportation created on the premise of mass transport, further increasing the dependence on automobiles. Many Japanese cities are still experiencing the effects of disurbanization (urban
decline), but some cities are trying to proceed to the reurbanization stage. The role of transportation inthis fourth stage is, in contrast to that during the suburbanization stage, connecting areas of agglomeration within the city at short distances and moderate speeds, and promoting interconnectedness between
these areas of agglomeration.
The heavily automobile-dependent United States has been often called a “suburban nation.”2) ,3)
However, the spread of road infrastructure and automobile use during the 20th century made it the“suburban era” for many countries worldwide. Those looking to escape from problems caused byincreased urban density due to increasing populations looked to suburbs as a kind of utopia that would
provide a wealthier countryside lifestyle, resulting in the mass production of largely uniform residential
and commercial suburban development all over the world. Artificially planned suburbs with decentralized and individualistic lifestyles were supported by freedom of movement for private car owners, andlater changed form into widespread sprawl development. This exacerbates the problem of automobile

Chapter 1: Cities and transportation｜13

Urbanization

Population growth andcongestion due to overcrowding• Provision of railways, etc.

Suburbanization

Population growth andurban expansion• Motorization• Long distances, high speeds

Disurbanization

Continuation of expansion anddecline• Motorization• Decline of public transportation

Reurbanization

Re-agglomeration of urban hubs
• Connected accessible
transportation• Short distances, low speeds

Figure 1. The urbanization process and the changing role of transportation

dependence, creating a negative synergistic effect between motorization and suburban sprawl.4)
The root of such urban and transportation problems is, in short, that our thinking regarding therole of transportation has halted at the suburbanization phase, considering that the goal of transportation must be “long distances, high speeds.” We must evolve our thinking to the reurbanization phase,where the goal is rather “short distances, low speeds.”

1.2

Mobility and accessibility

Mobility is generally defined as the ability to
move, and according to Ota 5) represents “theIndividuals

degree of freedom of general individual movement with no regard to specific destination.” Intransportation studies. Specifically, the word canalso be defined to mean the ease of reaching destinations and opportunities such as workplaces,
shopping, and medical services, or the ease withwhich one can make use of them. In recent years,
accessibility and usability have come to be a

ing
ell
Dw

y
vit

desired destinations.” The word “accessibility” isalso widely used in fields such as geography and(resources)ti
Ac

contrast, accessibility refers to “the ability to perform demanding activities through movement toAbil
re ity tso o u(m urc tilobe izilit s ey)

Place

Opportunity

Travel(service)(residence)
Ease
(acce

Freedomof choicesof reachssibility)Figure 2. The relation between mobility
and accessibility6)

14｜Theory

central concept in ideas in universal design.7)
Figure 2 shows the relationship between mobility and accessibility in a schematic form for a single
individual. Here, mobility is considered as the ability of an individual to make use of resources (time,money, external support and assistance, as well as environmental factors, etc.) through movement, andaccessibility as ease of reaching essential opportunities and services. The perspective of mobility captures the degree of human-centered freedom of choices, while that of accessibility captures the degree ofplace-based freedom as relating to the places that attract people. Our overall freedom of choices is determined by both mobility and accessibility.

1.3

Urban travel speed and safety

At the national level, emphasis should be placed on fast mobility to connect cities and hubs at high speedby the latest technologies, including a maglev Shinkansen and a logistics Shinkansen for the country’s
high-speed rail network. On the other hand, slow mobility for enjoying excursions and interactions at asafe and comfortable speed should be emphasized for personal and social reasons at the local level. Rigid
differentiation of travel speed according to location is required for achieving sustainable transportation
as well as increasing the attractiveness of cities.
In Japan, which is experiencing the problems of population decline and super-aging of society,large-scale shrinking of cities is required from the perspective of national land and urban management.
However, such severe constraints can also serve to foster creativity that can break through the impasseand lead to co-evolution of transportation, urban, and social developments. The development of “shrinking cities” to achieve sustainability and the development of “creative cities” to increase competitivenessare strategies that are two sides of the same coin, and the realization of both will require a reconfiguration of the bonds between the elements of people, knowledge, goods, services, money, and time. Mobility is the key to doing so. As mentioned in Section 1.2, mobility refers both to freedom of movement andability to make use of resources.
Building a mobility system for cities that are both sustainable and highly competitive will require a
multifaceted understanding of the value of mobility, along with the formation of a hierarchical network,
consisting of a fast mobility layer that connects cities and hubs at high speed and a slow mobility layer
within cities and hubs that promotes excursions and interactions at low to medium speeds. Slow mobility refers to means and forms of transportation at near-human speeds. But why is such distinction
between speeds necessary?
A negative aspect of motorization is its standardization of travel speed. Whether in towns, suburbs,
or between cities, most automobile drivers pursue speed. The desire for “long distances, high speeds”
mentioned in Section 1.1 is ever-present, whether one is inside or outside of urban areas.
The pursuit of speed regardless of places results in uniform expansion that impairs the hierarchy ofurban spaces. The result is longer daily trips to work and school, increased energy consumption fortransportation, increased production of CO2 and local environmental load, and even threats to life dueChapter 1: Cities and transportation｜15

Economy (efficiency)
Metropolitan
area
expansion

Hierarchicalstructureof networks

Total length ofroad and rail
networks

Distribution of population and employment
IncomegrowthDistribution of travel speed

Hierarchicalstructure ofurban spaces

Concentration anddispersion ofurban functions

Metropolitan
area
population

User benefit
Operator profits

Social (safety)

Speed between hubs

Value ofmobility

TDM, ITS
Smart choices

CO2 emissions
Environmental load

Speed within hubs

Ownership andusage ofautomobiles

Traffic fatalities
and injuries

Energy and the environment
Management of space,
speed, and demand

Figure 3. A causal relationship regarding the value of mobility and travel speed as the key factor

to increased risk of injury or death in a traffic accident (Fig. 3).
Figure 4 shows the relationship between urban population density, automobile travel speeds, andrates of road traffic deaths between 2008 and 2010 for 65 regional core cities with a population over
300,000 inhabitants in Japan. Bubble size in the figure represents the population of the city. From Fig. 4(a), one can clearly see that the rate of traffic fatalities increases with lowered urban density. Consideringthat this relationship may vary between cities due to differences in the development level and usage rates
of urban public transportation, we focused on only automobiles and analyzed the relationship between
population distribution and average automobile running speed for intra-city travel, as well as the relationship between average travel speed and traffic death rate. As the results in Figs. 4 (b) and (c) show, wefound causal relationships in which the more two-dimensionally dispersed a city was, the higher its
average automobile travel speed, and the higher the average travel speed, the higher the traffic death

6.0
5.0
4.0
3.0
2.0
1.0
0.0

0

5

10

15

DID population density (1000 people/ha)(a) Population density and road traffic death rate

50

7.0

45

6.0

Traffic fatalities per
100,000 population

Average travel speed (km/h)

Traffic fatalities per
100,000 population

7.0

40
35
30
25
20

0.4

0.6

0.8

1 .0

1.2

DID population ratio(DID population / city population)(b) Population distribution and average automobile
travel speed

5.0
4.0
3.0
2.0
1.0
0.0

20

30

40

Average travel speed (km/h)

50*DID: densely inhabited district(c) Average travel speed and road traffic death rate

Figure 4. Urban population density and distribution versus average automobile travel speeds and rates of road
trafﬁc deaths

16｜Theory

rate. 8) These results consider only the
relationship between density, speed, andsociety, the economy, and the environment, while keeping in mind the causal
relationships indicated by Figure 4.
One result of increasingly slower
movement speeds in urban areas and

Bus

50

Required time (minutes)

safety, so in the future there is a need toanalyze the effects of travel speed on

Walking60

BicycleAutomobile
Train

40
30
20
10

pursuit of the merits of slow mobility is0

the cycling revolution currently spreading in Europe. As shown in Figure 5, fortrips up to around 5 km bicycles have a

0

2

4

6

8

10

Distance traveled (km)Figure 5. Comparison of travel times by transportation mode for
intra-city travel

quicker travel speed than do automobiles and trains, and as is well known in Japan bicycles serve as an excellent, efficient and fast transportation mode within cities. The cycling revolution in London is famous for results such as its cycle superhighways and cycle hire (bike-sharing) scheme, but the social background and events leading up to thisrealization is rich in lessons. A series of socioeconomic factors such as soaring fuel prices starting
around 2002, the introduction of in-town road pricing in 2003, and subway and bus terrorist attacks in2005 are some of the influences that led people to use bicycles for their travel needs.

1.4

Aging and travel needs

As humans age they experience changes in physiological functions, reduced physical ability, reduced

In particular, the elderly placeless weight on the time and cost
aspects of travel, and more weight on

Abilitycognitive characteristics, and other changes in psychology and awareness that cause a decline in movement ability (Fig. 6). Figure 7 shows some of these mental changes that accompany increased age andresult in changes in travel needs.

Assumed previous
level of ability

travel that is safe, secure, and beneficial to health and the environment.
When this is displayed as a ternary
plot showing the positioning of vari-Assumed ability in a(super-) aged society• Changes in physiological function due to aging• Reduced physical ability• Decline in cognitive characteristics• Changes in psychology and awarenessous modes of transportation, the travelneeds in an aging society show a clear
shift up and to the right, representing
a shift toward demand for medium- to

0

20

40

60

80

Age

Figure 6. Changes in human ability accompanying age

per
che
a
nd
Fas
ter
a

0.2

25
–3
4
35 year–4s4y45 ears–54y
55 ear
s
–6
4y
ea
rs
65
+y
ea
rs
liv 65+ing yealo arsne ,0.0

Safety and security

Comfortable travel

Time and expense

Work and tasks

Health and the environment

35–44` 45–54
25–34 years

0.5
0.25

nity

65+
55–64

ma

0.4

Hu

0.6

bili
ty

tra
ve

l

0.8

Walking

0.5

Mo

0.25

1.0

th
eal
to h tial menefic ironben env
vel heTra and t

Weighting for quality of movement

Chapter 1: Cities and transportation｜17

Safe and secure travel

Current sense of values

0.25
0.50
Automobile

Publictransportation
Safety andtransportation capacity

10–15 years later

Figure 7. Changes in travel needs accompanying aging9), 10)

low-speed “slow mobility” that is located in the position between public transportation and privatetransportation. This is the position associated with transportation modes such as next-generation LRT
systems, low-speed electric community buses, community cycles, and other forms of shared personal
mobility.
Building the mobility system for a sustainable city will require a bold outlook on making thesechanges, and enhanced safety is the starting point of the change process. Doing so will require making
decisions on the priorities for and extensive management of speeds of road transportation. Efforts toachieve the harmonious coexistence of humans and automobiles through reducing speeds can be seenin European speed management programs such as the establishment of the “Zone 30” measure, which
establishes establish a 30 km/h (20 mph) zone. In recent years there have been increased efforts towardretaining comfortable space via improved road design that attempts to change driver behavior in waysthat reduce their running speed. There has also been a worldwide trend toward promoting “walkablecities,” which allow residents to walk to places necessary for daily life. These are some examples in whichhuman-centered prioritization has been established as the guiding principle for road and urban spacedesign.

1.5

Integrated design of cities and transportation

The term “integrated transportation” came into common use in the latter half of the 1990s. It goes without saying that a unified perspective is needed when developing transportation policy. The most important point is that one performs not an additive unification, but an integrated approach that combinesdiverse aspects into a whole. There are four levels in a desirable integrated transportation system:
1) Operational integration: integration of public transportation services, fare structures, and operation information
2) Strategy integration: integration of policy instruments for the infrastructure, management,

18｜Theory

information provision, and pricing between different transportation modes
3) Policy integration: integrated policies for transportation and land use; integrated policies between
transportation divisions and divisions for other areas such as the environment, health care,social welfare, education, and disaster prevention
4) Organizational integration: integration of the various organizations and institutions that are
responsible for transportation
Of the above, integrated transportation and urban design largely correspond to item 3), policy integration. In compact cities aiming for sustainability, as well as in transportation systems developed considering the needs of an aging society, addressing each of these in isolation will result in diminishedeffects. The expansion of cities seen in the twentieth century resulted from increased motorization androad development extended to far-reaching suburbs, in addition to population growth pressures. At aminimum, therefore, it is imperative to perform policy design of integrated transportation and urban
development.11), 12)
Figure 8 shows some of these integrated design concepts and procedures. The figure illustrates therelation of the four domains of city, infrastructure, mobility, and society; mobility is centrally locatedand is positioned as a system in which public transportation and personal mobility measures complement each other. “Road diets” refers to a method for creating space for pedestrians, bicycles and othermedium- to low-speed personal transportation modes by reducing the number and/or width of roadway
EconomyImprovement of overall efficiency
through allocating the righttransportation modes in the right places

Infrastructure
Mobility

Publictransportation Dynamic
linkage

TOD • Corridor

Districtcontinuation
program

Personal
mobility
measures

Road diet/renovation

Conversion to a compact
city through shrinking andre-agglomeration ofurban functions andspacesCompact and connected city

Environment

City

SafetyPriority and speed
management in roadtransportation

New infrastructure
ICT • Smart
Community

Community and new public

Community
infrastructure

Society

Design process
EquityTransition to a social systemstandardized on the elderlywith limited mobility

Figure 8. Integrated design of cities and transportation

Chapter 1: Cities and transportation｜19

lanes. This allows existing roads renovated with an emphasis on the usability of road spaces by a broader
range of users, and has already been implemented in many countries. In addition, transit-oriented development and corridor development are methods of supporting public and shared transportation from aland use aspect. Detailed discussions of these are presented in chapter 2.
As the design process loop in the figure shows, priority-based road space allocation and strict speed
management to secure traffic safety are the primary pursuit, and they result in the ability to render social
systems standardized on the elderly in which universal design can assist in providing increased accessibility. Also promoted is a conversion to compact cities in which urban functions and spaces are moreaggregated. When these conditions are met, regional public transportation becomes sustainable, and thestrategy of “allocating the right transportation modes in the right places” will lead to improved overall
efficiency. Implementing a mobility revolution will be impossible without holistic perspectives thatclearly prioritize management of speeds (slowness) and spaces (compactness), as well as time management that harnesses the opportunities and threats of external shocks and constraints, converting theseto revolutionary force. In Japan, there are continued trends for neglecting the global optimization intransportation policy; public transportation policy is still being discussed in isolation, and slow mobility
modes such as bicycles are positioned merely as local solutions without intermodal integration.
In a future of increasingly harsh economic and financial conditions, it will be difficult to improve
the quality of mobility in a super-aged society without meeting prerequisites of priority, slowness, andcompactness (PSC). Quality of mobility refers to social usability for users with diverse needs. Moving
beyond the physical, physiological, and ease-of-use levels of today’s “usable” mobility systems to a higher
level in which one psychologically wants to use the system will require a revolutionary process thatemphasizes PSC.
The view of linear growth that aims at an American- or European-style society has become lesseffective.13) Nevertheless, we find it difficult to abandon such concepts of growth in our pursuit of afuture mobility society. This is why our thinking on the role of transportation comes to a halt as
described at the beginning of this chapter. The development of a mobility society best suited to ourselves
will require consideration of not only technologies and systems, but also culture and ethos.

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