Title: Introduction%20to%20Travel%20Demand/Behavior,%20or%20What%20about%20the%20People%20in%20Transportation?
1Introduction to Travel Demand/Behavior, orWhat
about the People in Transportation?
- Prof. Patricia L. Mokhtarian,
- Dept. of Civil Environmental Engineering
- Institute of Transportation Studies
- University of California, Davis
- plmokhtarian_at_ucdavis.edu
- www.its.ucdavis.edu/telecom/
2Premise
- An understanding of individuals travel behavior
is important to - forecasting future travel demand
- evaluating the effectiveness of policies
- predicting the response to new technologies or
services - anticipating possible unintended consequences
3Overview
- Demand versus behavior
- Why do people travel?
- Trends in travel demand
- Modeling travel demand/behavior
- Policy measures and travel behavior
- Summary and conclusions
4Demand v. Behavior
Both deal with peoples travel choices/patterns/tr
ends
- Demand
- Aggregate
- Forecast
- TRB ADB40, Transportation Demand Forecasting
- Behavior
- Disaggregate
- Explain
- TRB ADB10, Traveler Behavior and Values
5Why do People Travel?
- (Why did the chicken cross the road?)
- Duh to get where they want to be???
- Hence, the truism that Travel is a derived
demand i.e. the demand for travel is derived
from the demand for spatially-separated
activities - Corollary Travel is a disutility, that people
try to minimize
6Assumed Implications (1)
- Saved travel time is a benefit, hence a basis for
valuing transportation improvements - THE largest benefit component in most
cost-benefit analyses - We can reduce travel by
- ... making it more expensive
- congestion pricing, fuel taxes, parking pricing
7Assumed Implications (2)
- We can reduce travel by
- bringing activities closer together
- increasing density and mixture of land uses
- using ICT to conduct the activity remotely
- telecommuting, -conferencing, -shopping,
-education, -medicine, -justice - We can better forecast travel by under-standing
peoples activity engagement the so-called
activity-based approach to modeling travel
demand
8But is that the only reason people travel -- to
get somewhere in particular?
9Why Would Travel be Intrinsically Desirable?
- Escape
- Exercise, physical/mental therapy
- Curiosity, variety-, adventure-seeking conquest
- Sensation of speed or even just movement
- Exposure to the environment, information
- Enjoyment of a route, not just a destination
- Ability to control movement skillfully
- Symbolic value (status, independence)
- Buffer between activities, synergy with multiple
activities
10Assertions
- Those characteristics apply not only to
undirected (recreational) travel, but to directed
travel as well - varying by mode, purpose, individual,
circumstance - Even if derived, travel can simultaneously be
intrinsically valued - in which case, people will be less inclined to
reduce it than an evaluation of its derived
nature alone would suggest
11Trends in Travel Demand
12U.S. Trends, 1950-2006 (1950 100)
13http//www.bts.gov/publications/bts_transportation
_trends_in_focus/2010_04_01/html/figure_03.html,
accessed 9/30/2011
14http//www.bts.gov/publications/bts_transportation
_trends_in_focus/2010_04_01/html/figure_04.html,
accessed 9/30/2011
15http//www.bts.gov/publications/special_reports_an
d_issue_briefs/special_report/2007_10_03/html/figu
re_01.html, accessed 9/30/2011
16Global Changes, 1960-1990
NAM N. America LAM Latin America WEU W.
Europe EEU E. Europe FSU Former Soviet
Union MEA Middle East and North Africa AFR
Sub-Saharan Africa CPA Centrally Planned Asia
and China SAS South Asia PAS Other Pacific
Asia PAO Other Pacific OECD
Motorized mobility (pkm) per capita, 1960 and
1990. Source Schafer, 1998
17pkm by mode, 1970-2001 (EU-15)
Source European Commission, 2003
18European Private Auto Passenger Travel, 1990-2008
19European Rail Passenger Travel, 1990-2008
20European Bus/Coach Passenger Travel, 1990-2008
21Ave. Annual Growth Rate of Cars and Their Use,
1970-90
Source USDOT, 1997, Figure 10-2, p. 231
22Auto Travel, 1970-2001 (EU-15)
Source European Commission, 2003
23Intra-European Airline Passenger-km, 1970-2001
Data source Eurostat/DGTREN. Source of figure
CNT, 2004
24International Airline Passengers, 1993-2001
Data source Eurostat. Source of figure CNT,
2004
25Per Capita km, 2001
Source European Commission, 2003
26Mobility as a Function of GDP
NAM N. America LAM Latin America WEU W.
Europe EEU E. Europe FSU Former Soviet
Union MEA Middle East and North Africa AFR
Sub-Saharan Africa CPA Centrally Planned Asia
and China SAS South Asia PAS Other Pacific
Asia PAO Other Pacific OECD
Motorized mobility (car, bus, rail, and aircraft)
per capita by world region vs GDP per capita,
between 1960 and 1990. Source Schafer, 1998
27Car Ownership v. GDP
SAS South Asia PAS Other Pacific Asia CPA
Centrally Planned Asia and China
Estimated motorization rates for CPA, PAS and
SAS, compared with the observed rise in
motorization in several countries. Source of
historical data United Nations, 1960 United
Nations, 1993a and IRF, various years. Source for
figure Schafer and Victor, 2000
28Projected Mobility, 2050
Historical and estimated future total global
mobility by mode in 1960, 1990, 2020 and
2050. Source Schafer and Victor, 2000
29Projected Mobility, 2050
Per-capita and total mobility for 11 regions (and
share of global total) in 1960, 1990, 2020, and
2050 for the reference scenario. NAM N.
America AFR Sub-Saharan Africa LAM Latin
America CPA Centrally Planned Asia and
China WEU W. Europe SAS South Asia EEU E.
Europe PAS Other Pacific Asia FSU Former
Soviet Union PAO Other Pacific OECD MEA Middle
East and North Africa Source Schafer and
Victor, 2000
30Modeling Travel Demand/Behavior
31Regional Travel Demand Forecasting (RTDF) (1)
- Or, the Urban Transportation Planning System
(UTPS) - The workhorse of metropolitan area planners (ECI
251) - forecast demand
- evaluate alternatives
- Calibrated with data from a large-scale
travel/activity diary survey (TTP 200)
32Regional Travel Demand Forecasting (RTDF) (2)
- The model contains 4 stages or submodels,
corresponding to a set of choices that
individuals are assumed to make - whether to travel (trip generation)
- where to travel (trip distribution)
- by what means (mode) to travel (mode choice)
- by what route (route assignment)
33Regional Travel Demand Forecasting (RTDF) (3)
- Example analysis tools used
- cross-classification, regression (trip
generation) - gravity model (trip distribution)
- probabilistic discrete choice ECI 254 (mode
choice) - network optimization ECI 257 (route assignment)
34Other Aggregate Demand Models
- Auto ownership
- Nationwide vehicle-miles traveled (VMT)
- Travel time is there a travel time budget?
- Fuel consumption
- Air travel demand
- TOOLS
- Regression
- Time series
- Structural equations modeling
35Disaggregate Behavioral Models/Tools
- ANOVA, regression
- Discrete choice (residential location, auto
ownership, of trips, destination, mode, route,
combinations)
36Discrete Choices of Work/Commute
Engagement/Location
- Work engagement work frequency commute
frequency
37Discrete Choices of Work/Commute
Engagement/Location
- Work engagement commute engagement type of
partial commute
38Disaggregate Behavioral Models/Tools
- ANOVA, regression
- Discrete choice (resid. loc., auto own., of
trips, destination, mode, route, combinations) - Hazard models (activity durations, how long a
vehicle is owned, time till accident, length of
tele-commuting engagement) - Factor analysis TTP 200 (attitude/opinion
measurement) - Structural equations modeling (relationships
among attitudes, residential location, and travel
behavior relationships between telecom and
travel)
39Structural Model of Mobility Preferences/Behavior
40Structural Model of Telecom/ Travel Relationships
Socio-demographics
Economic Activity
Travel Demand
Telecommuni-cations Demand
Transporta-tion System Infrastructure
Telecommuni- cations System Infrastructure
Telecommuni-cations Costs
Travel Costs
Land Use
Endogenous Variable Category
Exogenous Variable Category
41Relationships among Attitudes, Land Use, Travel
Behavior
42Policy Measures and Travel Behavior
43When you think about it, virtually ALL policies
are intended to affect behavior, whether they are
...
- supply-oriented, or
- demand-oriented
44Supply-oriented Policies
- Expand physical infrastructure
- Does this in itself stimulate the realization of
latent demand? - More effectively manage existing supply
(Transportation Supply Management, TSM) - Increase supply or reduce costs
- to underserved populations
- of using non-auto modes
45Demand-oriented Policies
- Generally intended to reduce demand, by
- changing the cost signals (internalizing
externalities, i.e. raising costs!) - changing land use planning to bring activities
closer together - promoting ICT substitution
- Collectively referred to as Transportation Demand
Management (TDM) strategies
46Summary
- People travel for many reasons besides the
obvious one it is a fundamental human need - Worldwide trends are toward more travel, not just
due to population growth, but per capita - It is a challenge to balance the human need for
mobility against the need for sustainability - We need to better understand the need to travel
for its own sake, and reasons behind various
travel decisions - Implications for modeling, evaluation, policy
47Discussion Questions
- DOES virtual mobility reduce the need for real
mobility? - How can we balance the human need for mobility
against the need for sustainability? - Should policymakers try harder to discourage
unnecessary travel? What are the most
effective ways of doing so? - Can people express the extent to which they
travel for its own sake?
48Other Questions?
plmokhtarian_at_ucdavis.edu www.its.ucdavis.edu/telec
om/
Slide borrowed from David Ory
49Selected References
- CNT (Conseil National des Transports, Observatory
on Transport Policies and Strategies in Europe)
(2004) Bulletin Transports/Europe No. 11.
Available at www.cnt.fr. - European Commission (2003) European Union Energy
Transport in Figures. Directorate-General for
Energy and Transport. - Handy, Susan (2002) Accessibility- vs.
mobility-enhancing strategies for addressing
automobile dependence in the US. Prepared for
the European Council of Ministers of Transport
Roundtable 124, on Transport and Spatial
Policies, November 7-8, Paris. - Houseman, Gerald (1979) The Right of Mobility.
Port Washington, NY Kennikat Press. - Mokhtarian, Patricia L. Cynthia Chen (2004) TTB
or not TTB, that is the question A review and
analysis of the empirical literature on travel
time (and money) budgets. Transportation
Research A 38(9-10), 643-675. - Mokhtarian, Patricia L. Ilan Salomon (2001) How
derived is the demand for travel? Some
conceptual and measurement considerations.
Transportation Research A 35, 695-719. - Schafer, Andreas (1998) The global demand for
motorized mobility. Transportation Research A
32(6), 455-477. - Schafer, Andreas and David G. Victor (2000) The
future mobility of the world population.
Transportation Research A 34(3), 171-205. - U. S. Department of Transportation (1997)
Transportation Statistics Annual Report 1997
Mobility and Access. Washington, DC USDOT
Bureau of Transportation Statistics. Available
at http//www.bts.gov/publications/transportation_
statistics_annual_report/1997/pdf/report.pdf.