«Technical Report Documentation Page 1. Project No. 2. Government Accession No. 3. Recipient's Catalog No. SWUTC/11/161127-1 4. Title and Subtitle 5. ...»
Technical Report Documentation Page
1. Project No. 2. Government Accession No. 3. Recipient's Catalog No.
4. Title and Subtitle 5. Report Date
Understanding Emerging Commuting Trends in a Weekly September 2011
Travel Decision Frame--Implications for Mega Region
6. Performing Organization Code Transportation Planning
7. Author(s) 8. Performing Organization Report No.
Ming Zhang and Binbin Chen Report 161127
9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Center for Transportation Research University of Texas at Austin
11. Contract or Grant No.
1616 Guadalupe, Suite 4.202 Austin, TX 78701
12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Southwest Region University Transportation Center Final Report Texas Transportation Institute
14. Sponsoring Agency Code The Texas A&M University System College Station, TX 77843-3135
15. Supplementary Notes Supported by general revenues from the State of Texas.
16. Abstract National transportation statistics have shown the rise of long-distance, trans-regional commute (LDC/TRC) in the US. Four societal factors contribute to the trend: increase in dual earner households, advance in information and communications technologies, new concept of arranging work time weekly, and people's changing attitude towards travel. In the field of urban transportation planning, commuting has been studied in individual metropolitan areas in a one-day time frame. LDC/TRC traverse multiple metros and the commuting behavior cannot be better understood without going beyond the one-day convention. Studying LDC/TRC corresponds to the growing interest worldwide in planning for megaregions. Up to date, the phenomenon of weekly commuting has been explored only by a few European researchers in the fields of geography and sociology.
This study analyzed LDC/TRC using national datasets available in the US. They are American Travel Survey, National Household Travel Survey, and Census Transportation Planning Package. Further detailed analyses were conducted for the Texas Triangle megaregion. The national travel surveys are helpful in
The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. This document is disseminated under the sponsorship of the Department of Transportation, University Transportation Centers Program, in the interest of information exchange. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
Dr. Daniel Yang (Project Monitor) at the Capital Area Metro Planning Organization (CAMPO), Austin, TX provided invaluable help to the project. Any errors remain the responsibilities of the authors.
The authors recognize that support for this research was provided by a grant from the U.S.
Department of Transportation, University Transportation Centers Program to the Southwest Region University Transportation Center, which is funded, in part, with general revenue funds from the State of Texas.
vvi Table of Contents
List of Figures
List of Tables
2. Societal Factors Influencing Trans-Regional Commute
2.1. Increase in Dual Earner Households
2.2. New Information and Communications Technologies
2.3. New Concept of Arranging Work Time
2.4. People's Changing Attitude Towards Travel
3. Studies on Long-Distance Commuting (LDC) / Trans-Regional Commute (TRC)....... 9 3.1. Commuting and Job/Home Locations
3.2. Long Distance Commuting within One Metropolitan Area
3.3. Long Distance Commuting across Regions
3.4. Long Distance Weekly Commuting
3.5. Migration vs. Commuting
3.6. Commuting couples - the sociology & psychology perspectives
4. Analytical Methods to Study LDC/TRC
4.1. Intercity Travel Demand Model
4.2. Mode Choice modeling
4.3. Application Example: Intercity Bus Transportation
4.4. Application Example: Forecast Ridership for New Mode (HSR)
5. Empirical Studies with National Datasets
5.1. The 1995 American Travel Survey (ATS)
5.2. Census Transportation Planning Package (CTPP) and National Household Travel Survey (NHTS)
5.3. The Analysis of the CTPP data
5.4. The Analysis of the NHTS data
5.5. Long Distance Commute in the Nation
vii 5.6. Long Distance Work Flow Directions in Texas
5.7. Limitation of Using Secondary Travel Survey Data
6. Summary and Future Research
6.1. Summary of Preliminary Study
6.2. Future Research
Figure 1: Intercity Decision Making
Figure 2: Overview of different random utility models
Figure 3: Long Distance Commute Flow Directions in Texas (2001a)
Figure 4: Long Distance Commute Flow Directions in Texas (2001b)
Figure 5: Long Distance Commute Flow Directions in Texas (2009)
Table 1: Percentage Changes of Total and Interregional Commuters from 1990 to 2000.. 33 Table 2: Commuting Flow between Regions in the Texas Triangle Area (1990)............... 34 Table 3: Commuting Flow between Regions in the Texas Triangle Area (2000)............... 34 Table 4: Percent of Trips (long-distance) by Trip Purpose
Table 5: Percent of Trips (long-distance) by mode for One-way Travel Distance.............. 36 Table 6: Percent of Trips (long-distance) by mode for Household Income Groups............ 36 Table 7: Percentage of Long Distance Commuters
Table 8: 2001 Long Distance Commute Composition
Table 9: 2009 Long Distance Commute Composition
Table 10: Long Distance Commuting Mode Share
Table 11: Leave Home and Return Home Time
Table 12: Long Distance Commute VMT
Table 13: Variables in Models
Table 14: Model Results
National transportation statistics have shown the rise of long-distance, trans-regional commute (LDC/TRC) in the US. Four societal factors contribute to the trend: increase in dual earner households, advance in information and communications technologies, new concept of arranging work time weekly, and people's changing attitude towards travel.
In the field of urban transportation planning, commuting has been studied in individual metropolitan areas in a one-day time frame. LDC/TRC traverse multiple metros and the commuting behavior cannot be better understood without going beyond the one-day convention. Studying LDC/TRC corresponds to the growing interest worldwide in planning for megaregions. Up to date, the phenomenon of weekly commuting has been explored only by a few European researchers in the fields of geography and sociology.
This study analyzed LDC/TRC using national datasets available in the US. They are American Travel Survey, National Household Travel Survey, and Census Transportation Planning Package. Results show that,
• Nationwide, the percentage of long distance commuters increased from 2.8% in year 2001 to 2.9% in year 2009. The South Census Region which Texas belongs to had the highest percentage of long distance commuters at 3.1% in 2009.
• Among long distance commuters, more than 80% traveled 50 to 100 miles to work, and less than 3% traveled over 300 miles to work. The main travel means for long distance commute was private car; more than 90% of long distance commuters drove private cars to work and more than 80% of them drove alone.
• The vehicle miles traveled (VMT) by the 3% of long distance commuter accounted for 16% of VMT by all commuters in 2001 and 13% in 2009, respectively. The decline in VMT suggests a shift in mode choice over time from driving to nondriving.
• Long distance commuters spent more time away from home, leaving home earlier and return home later than normal commuters. Male commuters tend to travel longer distances than female. If a person has options to work at home occasionally, he or she tends to commute long distance.
• In Texas, 70% of commutes with distance of 50 miles or longer was interregional, and more than 70% of the long distance commutes in Texas was within the Texas Triangle Area.
The national travel surveys are helpful in portraying large pictures of LDC/TRC but limited in offering insights into LDC/TRC behavior. Based on the preliminary study, the next phase of the study will conduct qualitative research by interviewing selected LDC/TRC individuals in the Texas Triangle megaregion.
xixii 1. Introduction
Travel demand analysis has focused conventionally on activities and trips performed by household members in a given survey day. Such a one-day focus is plausible because human activities, for example, commuting, schooling and sleeping, cycle in a one-day time span due to physiological and institutional reasons.
Many emerging commuting trends however cannot be better understood without going beyond the conventional one-day travel decision frame. One emerging trend is the increase of longdistance commute (50-100 miles each way) and specifically the increase of the extreme commute (one-way journey to work distance longer than 90 miles). In 2005, 3.4 million people in the US undertook extreme commute, doubling the number in 1990 (Naughton 2006). Studying multi-day travel, for instance, one week, would offer insights into the growing long-distance or extreme commute. Kitamusa (1988), among other scholars, has stressed the importance of using multiday data to examine day-to-day variations in travel patterns in order to address the likely biased representation of travel behavior in the one-day data sets. Yet there have been limited studies along this line of inquiries mainly because of the limited availability of multi-day data.
Another trend pertains to telecommuting. Telecommuting has become a recognized mode of (virtual) travel. Although the total substitution of telecommuting for physical travel is unlikely for all occupations, partial substitution by telecommuting one or more days a week and traveling physically the rest of the week is increasingly popular (Collantes and Mokhtarian, 2003).
Understanding the implications of telecommuting for physical travel requires a time unit of analysis longer than one day.
Commuting has served for the U.S. Census Bureau as an important indicator of economic integration in spatially delineating metropolitan areas. Much of the long-distance or extreme commute mentioned above involves trans-metropolitan travel—travelers living in one metropolitan area but working in another (Lang and Nelson 2007). A growing share of the long physical commute is coupled with telecommuting, the outcome of multi-day trip-making decisions. Anecdotal evidence from the Texas Triangle megaregion suggests that a growing number of people live in Austin and work in Houston (or vise versa) through a combination of telecommunicating and physical commuting on a weekly basis. Studying trans-metropolitan commuting provides evidence to support travel demand analysis and strategic transportation plan-making at the megaregion level.
The report presents a preliminary study for better understanding of the rising long-distance, trans-regional commute in a behavioral decision frame beyond the one-day convention. It is part of a broader effort to propose transportation planning strategies for megaregions. The report first reviews societal factors that influence long distance, trans-regional commute. It then synthesizes the literature on analytical methods and empirical evidence pertaining to trans-regional commute.
Empirical analysis with use of national data on the Texas Triangle is presented next. Finally the report summarizes study findings and suggests directions for future research.
2. Societal Factors Influencing Trans-Regional Commute
Commuting to a large extend is derived from the demand for participating in socioeconomic activities. For instance, people commute to work not for traveling per se, but mainly for earning income from work. Hence understanding changes in socio-demographic characteristics of individuals and households helps better understand commuting trends. Advances in information and communications technologies enable individuals to arrange flexible work schedules or to make commuting time less wasteful (Mokhtarian and Salomon 2001). This section reviews four trends that have reshaped the social environment and people's daily life that in turn influence people's commuting. They include increase in dual earner households, advance in information and communications technologies, new concept of arranging work time weekly, and people's changing attitude towards travel.
2.1. Increase in Dual Earner Households
One important change in the American family in the past 40 years has been the increase in women’s participation in the labor market. According to the US Bureau of Labor Statistics, the female labor force increased from 43% in 1970 to 60% in 2008, and women's share of work market increased from 38% to 47% during the same time period (US Bureau of Labor Statistics, 2009). As more women are earning college degrees, the number of career-oriented women has been rising. These higher educated women are more likely to continue pursuing their careers even after marriage. Consequently, the share of traditional one-earner households has been declining and dual- or two-earner households have been on the rise. In 2007, 62% of households had two earners compared to 24% of households with only one earner (US Bureau of Labor Statistics, 2009).