1

Preferred citation style

Axhausen, K.W. (2001) Social networks and travel behaviour, ESRC Workshop „Mobile network seminar series - Seminar 2: New communication technologies and transportation systems“, Lucy Cavendish College, Cambridge, February 2002.

Social networks and travel behaviour

KW Axhausen

IVTETHZürich

February 2002

3

A word of warning

An engineer talking about daily life and its underlying social structures puts himself at risk.

I am happy to take the risk and look forward to the critique and comments, as

• We need to underpin our travel behaviour models with a better understanding of the social structures of daily life

and, as

• We implicitly forecast/speculate about them when we predict travel behaviour over long time horizons, anyway

4

A look back: Productivity growth since 1000 (W Europe)G

alor

und

Wei

l (20

00)

0.00

0.50

1.00

1.50

2.00

2.50

3.00

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

Year

Gro

wth

rat

e [%

/yea

r]

ProductivityPopulation

5

A look back: pkm/day since 1850 (France)

0

10

20

30

40

50

1840 1860 1880 1900 1920 1940 1960 1980

Year

km/P

erso

n an

d da

y

Motorised individual modesPublic transportSlow modes

Gru

ber

(199

8)

6

A look back: GDP, Car and telephone ownership (CH)

0

250

500

750

1890 1910 1930 1950 1970 1990

Year

Num

ber/

1000

res

iden

ts

0

200

400

600

GD

P (

1913

= 1

00)

Telephone Mobile phone

Cars Internet userGDP

7

A look back: Average consumption of housing (CH)

0

15

30

45

60

1950 1960 1970 1980 1990

Year

Gro

ss a

rea/

hea

d [m

2]

CentresAgglomerationRegional centresRural villagesMountain villagesSwitzerland

Rum

ley

(198

4); K

elle

r

8

A look back: Household size (CH)S

iege

ntha

ler

and

Ritz

man

n-B

licke

nsto

rfer

(19

96)

0

1

2

3

4

5

6

1850 1870 1890 1910 1930 1950 1970 1990

Year

Mea

n ho

useh

old

size

[]

Central SwitzerlandAlpine cantonsNE - SwitzerlandNW - SwitzerlandRomandieSwitzerland

9

Look back: Distribution of personal time (UK)

0%

20%

40%

60%

80%

100%

1860 1880 1900 1920 1940 1960 1980 2000

Year

Life

time

shar

e [%

]

RetirementLeisure and otherWorkHigher educationChildhood and schooling

Gru

ber

(199

8)

10

Summary for the look back

Extraordinary income streams have been created and are consumed (in part) as

• Travel (Speed)• More (and dispersed) housing • Long-distance communication• Longer lives with less work

• Independence/Isolation

11

Daily life: Trip purposes (Uppsala 1971/Karlsruhe 1999)S

chlic

h an

d S

chön

feld

er

0 10 20 30 40 50

Other

Work-related business

Pick up/drop off

Long-term shopping

Education

Private business

Daily shopping

Work

Leisure

Return home

Share of all trips [%]

Uppsala (weighted)Karlsruhe Mobidrive

12

Daily life: Leisure (Uppsala 1971/Karlsruhe 1999)S

chlic

h an

d S

chön

feld

er

0 10 20 30 40

Meeting relatives

Window Shopping

Excursion: Culture

Club meeting

Other

Going for a walk and hiking

Active sports

Going out in the evening

Meeting friends

Share of all leisure trips [%]

Uppsala (weighted)

Karlsruhe Mobidrive

13

Daily life: Rythms in Uppsala 1971/Karlsruhe 1999S

chlic

h

14

Daily life: Rythms in Karlsruhe 1999 (56 day survey period)K

önig

15

Daily life: Local activity space of a car (Borlänge 2001)

Locations visited during a 3 month period by one carS

chön

feld

er

16

Daily life: Example activity spaces (Karlsruhe 1999)S

chön

feld

er

Ellipses cover the 95% confidence intervals of the locations visited

17

Summary: Daily life

Households are self-selected/trapped into the vector of

• Home location• Work/school locations• Mobility tools

Dominant shares of

• Leisure trips• Household maintenance trips

18

Social networks: Draft categorisation

• Family• Friends• Hobby (Animal care)• Sport• Civic engagements• Church

• Neighbours

• School/education• Work (one or multiple networks ?)• (Military/Civilian service)

• Service providers

19

Social networks: Possible transport questions

• Physical spatial-temporal coherence/overlap (constraints)

• Replacement of physical and telecommunication-based contact

• Interaction frequency and spatial reach

• Interaction and information/knowledge transfer

20

Question of spatial coherence (Network 1)

21

Question of spatial coherence (Networks 1 & 2)

22

Question of spatial coherence (Network 1, 2 & 3)

23

Social networks: Possible sociological questions

• Openness/replacement dynamics of the membership• Structure and definition of the network boundaries• Revival of contact/repair of links

• Shared skill/learning• Transfer/transmission of reputation• Transfer of resources/social capital

• Spatial and social reach (“6 degrees of separation” ?)

• (Time/money/social capital) Cost of maintenance

24

Social networks: Hypotheses

1. Local spatial-temporal coherence is lower than 1950

Why ?• The unity of work, residence and „Sozialmileu“ has been

broken for most people (e.g. long-distance commuting)

• Educational/employment paths are less uniform (in space)

• Mass customisation in travel (car), consumption and leisure (channel flood in entertainment)

25

Social networks: Hypotheses

2. The number of the current members is larger than in the past

Why ?• Money costs of contact have been dramatically reduced

(telephone, email, letter/xeroxing)• Easier projection of self (email, xeroxing) allows more social

grooming (Dunbar’s about 100) • Time/money costs of in-person contact with spatially distant

contacts have become – relatively – affordable (i.e. cheap long-distance travel)

2* Statements about the contact intensity distributions are difficult, as the increase in leisure time might balance the larger number of members

26

Social networks: Hypotheses

3. Time costs of network maintenance are larger than in the past

Why ?• Less chance of chance encounters• Lower local spatial network densities • Less opportunity to use proxies for messaging• Higher search costs (locating the person) (but for email,

mobiles, answering machines)

• Higher time costs to get to most members of the net• Longer catching-up times

27

Hypotheses visualised (Networks 1, 2 & 3)

28

Social networks: Externalities

• Stronger selectivity ?

• Less local inclusion ? (More commercial/institutional personal services ?)

• Less local generalised trust ? (feeling of safety and reliability)

• Car/paid travel dependence ?

29

(Concurrent) Spatial developments

Economically

• Increased specialisation of locations (regionally, internationally)

• Increased firm size in services and production• Increased market sizes at all scales

Urban

• Increased scales• Lower local densities

30

Spatial developments: Externalities

• Car/paid travel dependence ?

• Transport emissions (Noise, CO2, HC etc.)

• Loss of the common pedestrian environment• Arrival of the themed pedestrian environment

• Spatial segregation (locally, regionally)

31

Urban structure: Portland, OR, circa 1860

1 Mile

Jaco

bs (

1993

) 23

8

32

Urban structure: Commercial Irvine, CA, circa 1980

1 Mile

Jaco

bs (

1993

) 22

1

33

Urban structure: Residential Irvine, CA, circa 1980

1 Mile

Jaco

bs (

1993

) 22

2

34

Required networking tools

• Car (budget for taxi)• Budget for long-distance travel• (Mobile) phone • Location-free contact point (answering service, email, web-

site)

• Time to manage the above

35

Expenditure for those tools (CH)

0

10

20

30

40

50

1840 1860 1880 1900 1920 1940 1960 1980 2000

Year

Sh

are

of d

isp

osa

ble

inco

me

[%]

Food

Housing

Education & leisure

Transport andcommunications

Wid

mer

(20

01)

19

36

What now ?

Transport:• Better management of resources (demand-responsive

operation)• Demand-responsive pricing • Pricing of externalities

Socially:• Better time organisation

• Common scheduling tools• Reorganisation of working time

• Demand-responsive service delivery

37

What now ?

Spatially:

• Better pricing of externalities• Growth boundaries• Rescaling of the environments• Rebuilding the buildings/infrastructures of the post-war

period

• (Subsidised) local service points/local shopping facilities

38

This utopia ? (Greifswald, 1821)ho

me.

t-on

line.

de/h

ome/

k-j.l

ebus

/cdf

-hgw

.htm

39

Or this ? (Le Corbusier, 1922) F

ishm

an (

1982

)

40

Or that ? (Frank Lloyd Wright, 1945)

41

Literature

Axhausen, K.W. (2000) Geographies of somewhere: A review of urban literature, Urban Studies, 37 (10) 1849-1864

Congress for New Urbanism (2000) Charter of the New Urbanism: Region; Neighborhood, District and Corridor; Block, Street and Building, McGraw Hill, New York

Fishman, R. (1992) Urban Utopias in the Twentieth Century: Ebenezer Howard, Frank Lloyd Wright, Le Corbusier, MIT Press, Cambridge.

Galor, O. and D.N. Weil (2000) Population, technology, and growth: From Malthusian stagnation to the demographic transition and beyond, American Economic Review, 90 (4) 806-828.

Gruber, A. (1998) Technology and Global Change, Cambridge University Press, Cambridge.

42

Literature

Jacobs, A.B. (1993) Great Streets, MIT Press, Cambridge.

Putnam, R.D. (1999) Bowling Alone: The collapse and revival of American community, Schuster and Schuster, New York.

Rumley, P.A. (1984) Amenagement du territoire et utlisation du sol, Dissertation, ORL, ETH Zürich, Zürich.

Siegenthaler, HJ. and H. Ritzmann-Blickenstorfer (eds.) (1996) Historische Statistik der Schweiz, Chronos, Zürich

Simma, A. and K.W. Axhausen (Im Druck) Structures of commitment and mode use: A comparison of Switzerland, Germany and Great Britain, Transport Policy.

Widmer, J.P. (2001) Ausgewählte Schweizer Zeitreihen zur Verkehrsentwicklung, Materialien zur Vorlesung Verkehrsplanung, 1.02, IVT, ETH Zürich