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. 1
Social networks and travel behaviour KW Axhausen IVT ETH Zürich February 2002
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 3
A look back: Productivity growth since 1000 (W Europe) 3.00 2.50 Productivity Population Growth rate [%/year] 2.00 1.50 1.00 Galor und Weil (2000) 0.50 0.00 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 Year 4
A look back: pkm/day since 1850 (France) 50 km/person and day 40 30 20 Motorised individual modes Public transport Slow modes Gruber (1998) 10 0 1840 1860 1880 1900 1920 1940 1960 1980 Year 5
A look back: GDP, Car and telephone ownership (CH) 750 600 Number/1000 residents 500 250 Telephone Cars GDP Mobile phone Internet user 400 200 GDP (1913 = 100) 0 1890 1910 1930 1950 1970 1990 Year 0 6
A look back: Average consumption of housing (CH) 60 Rumley (1984); Keller Gross area/head [m2] 45 30 15 0 Centres Agglomeration Regional centres Rural villages Mountain villages Switzerland 1950 1960 1970 1980 1990 Year 7
A look back: Household size (CH) 6 Siegenthaler and Ritzmann-Blickenstorfer (1996) Mean household size [] 5 4 3 2 1 0 Central Switzerland Alpine cantons NE - Switzerland NW - Switzerland Romandie Switzerland 1850 1870 1890 1910 1930 1950 1970 1990 Year 8
Look back: Distribution of personal time (UK) 100% Lifetime share [%] 80% 60% 40% Retirement Leisure and other Work Higher education Childhood and schooling Gruber (1998) 20% 0% 1860 1880 1900 1920 1940 1960 1980 2000 Year 9
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 10
Daily life: Trip purposes (Uppsala 1971/Karlsruhe 1999) Return home Leisure Work Daily shopping Private business Education Schlich and Schönfelder Long-term shopping Pick up/drop off Work-related business Other 0 10 20 30 40 50 Share of all trips [%] Uppsala (weighted) Karlsruhe Mobidrive 11
Daily life: Leisure (Uppsala 1971/Karlsruhe 1999) Meeting friends Going out in the evening Active sports Going for a walk and hiking Other Schlich and Schönfelder Club meeting Excursion: Culture Window Shopping Meeting relatives Uppsala (weighted) Karlsruhe Mobidrive 0 10 20 30 40 Share of all leisure trips [%] 12
Daily life: Rythms in Uppsala 1971/Karlsruhe 1999 Schlich 13
Daily life: Rythms in Karlsruhe 1999 (56 day survey period) König 14
Daily life: Local activity space of a car (Borlänge 2001) Schönfelder Locations visited during a 3 month period by one car 15
Daily life: Example activity spaces (Karlsruhe 1999) Ellipses cover the 95% confidence intervals of the locations visited Schönfelder 16
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 17
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 18
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 19
Question of spatial coherence (Network 1) IVT: IVT: Location Location of of the the members members of of network network 11 of of the the person person in in the the centre centre (yellow (yellow dot) dot) 20
Question of spatial coherence (Networks 1 & 2) IVT: IVT: Networks Networks 11 and and 22 overlaid, overlaid, showing showing joint joint membership membership 21
Question of spatial coherence (Network 1, 2 & 3) IVT: IVT: Ditto Ditto for for network network 3; 3; showing showing the the density density of of relations relations and and interactions interactions between between the the memebrs memebrs 22
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 23
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) 24
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 25
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 26
Hypotheses visualised: Situation today (Networks 1-3) 27
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? 28
(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 29
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) 30
Urban structure: Portland, OR, circa 1860 Jacobs (1993) 238 1 Mile 31
Urban structure: Commercial Irvine, CA, circa 1980 Jacobs (1993) 221 1 Mile 32
Urban structure: Residential Irvine, CA, circa 1980 Jacobs (1993) 222 1 Mile 33
Required networking tools Car (budget for taxi) Budget for long-distance travel (Mobile) phone Location-free contact point (answering service, email, website) Time to manage the above 34
Expenditure for those tools (CH) 50 Widmer (2001) 19 Share of disposable income [%] 40 30 20 10 0 Food Housing Education & leisure Transport and communications 1840 1860 1880 1900 1920 1940 1960 1980 2000 Year 35
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 36
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 37
This utopia? (Greifswald, 1821) home.t-online.de/home/k-j.lebus/cdf-hgw.htm 38
Or this? (Le Corbusier, 1922) Fishman (1982) 39
Or that? (Frank Lloyd Wright, 1945) 40
Or something new? 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 43
Commitment effects: Mode choice Trips with motorized vehicles/week 20.0 15.0 10.0 5.0 Vehcile and season ticket No vehicle, but season ticket Vehicle, but no season ticket Neither CH CH German Panel Mikrozensus Schweiz UK National Travel Survey 0.0 0.0 2.0 4.0 6.0 8.0 Public transport trips/week 44
Hypotheses visualised 45