Elaine Murakami

Examining Trip-Chaining Behavior: Comparison of Travel by Men and Women

Gender and household life cycle together affect daily travel behavior. Although this makes intuitive sense, transportation planners and policy makers have done little to understand what effect and impact these factors have on daily transportation choices. The 1995 Nationwide Personal Transportation Survey was used to examine trip-chaining behavior of adult men and women traveling Monday through Friday. The data show that women continue to make more trips to perform household-sustaining activities such as shopping and family errands to a greater extent than men. Women, especially with children in the household, are more likely to chain these household-sustaining trips to the trip to and from work. Women’s participation in the labor force is at an all-time high, but women’s patterns in travel to work are different from men’s patterns, and they vary with family and life-cycle status. The type and location of jobs that women take are likely affected by their greater household and family responsibilities. The biggest question for the future is whether and how the changes in women’s status in the workplace, and perhaps the concomitant change in the household dynamics and responsibilities, will affect travel behavior of both men and women. These changes will deeply affect the development of programs related to transit, land-use planning, work schedules, telecommuting, and other programs related to automobile use.

THE PUGET SOUND TRANSPORTATION PANEL AFTER TWO WAVES

Begun in 1989, the Puget Sound Transportation Panel is the first general-purpose travel panel survey in an urban area in the United States. The overall survey sample was stratified by county of residence and by usual mode of travel to work. This paper reports descriptive results from the first two waves of survey data. Panel attrition between these waves was about 19 percent of all households. There was some demographic bias in panel attrition. The paper documents changes among the retained households in their demographics, their residence and work locations, their trip making, their work trip lengths, and their travel mode to work. Residential moves were numerous among young adults and young families, more outward from the city core than inward, and correlated with changes in work trip length. Work locations changed for 20 percent of continuing workers, with a tendency to increase trips and work trip length, and to change travel mode after a relocation. For all workers, there were clear shifts from transit to drive alone, from carpool to drive alone, and from drive alone to carpool as well. The PSTP continues, with a modified third wave in 1991, and a fourth wave scheduled in 1992.

Catching the Next Big Wave: Do Observed Behavioral Dynamics of Baby Boomers Force Rethinking of Regional Travel Demand Models?

The aging of American baby boomers creates various new policy contexts and problems. Depending on institutional preparedness and baby boomers’ behavior, the changing demand for transportation services by this group may be positive or negative. This potential change in demand is described through an analysis of individual longitudinal histories over a long period (1989 to 2003) that explores the effects of personal changes (e.g., entry to and exit from the labor force), household changes (e.g., relocation and dissolution), and changes in land use characteristics. The Puget Sound Transportation Panel (PSTP)—a record of approximately 20,000 travel diaries of Seattle residents, each of whom provided 2-day reports for 10 repeated contacts (waves)—was used. Within-household dynamics and the effect of within-household change on individual and household behavior are studied. Focus groups are used to extract behavioral themes, latent class cluster analysis is used to identify groups of behavior, and an array of regression models of change is used to identify the key determinants that underlie behavioral dynamics. Findings include a need to focus on employment, heterogeneity in land use impact, and the significant effect of household composition. Together, the findings imply the need for models that can handle more diverse behavior and the need to accommodate employment status and within-household demographics in forecasting models.

Working Retirement: Travel Trends of the Aging Workforce

The proportion and number of older workers (those older than 65) are expected to increase significantly in the coming decades, and examining this cohorts travel behavior may provide insight into this potential boom. This study is an exploratory analysis to describe working patterns of the older population today, to examine their work trips, and to make some guesses about how the baby boom generation will be similar to or differ from todays older population. With the available literature on travel by the elderly and data from the 2000 U.S. decennial census and the 2001 National Household Travel Survey, the commute and occupational characteristics of older workers in the work force are explored. Topics covered include projected increase in miles driven by older population groups, trends in labor force participation, occupations of older workers, overall travel patterns, travel time, and mode-to-work characteristics; examination of race and ethnic origin of older workers; and description of the older work-...

METAANALYSIS OF TRAVEL SURVEY METHODS

Travel surveys often serve as the primary sources of information on travel demand characteristics. They provide critical data for transportation planning and decision making. In recent times, several factors motivate a comparative examination of travel survey methods. First, new travel demand modeling tools, such as those based on activity-based methods, are placing greater demands on travel behavior data gathered from household travel surveys. Second, response rates from household travel surveys have been showing a steady decline, possibly because of an increasingly survey-fatigued population. Third, declining resource availability at metropolitan planning agencies places emphasis on the need to maximize response rates to lower data collection costs per completed respondent. Ideally, a comparative examination of travel survey methods is best done through a carefully constructed experimental design that permits the isolation of the impact of various survey design parameters on response rates. However, the conduct of such a controlled experiment virtually is impractical. A metaanalysis of a sample of travel surveys conducted in the past 10 years is presented. A predictive model of response rates is developed by using linear regression techniques and the practical application of the model is demonstrated through several numerical examples.

Development of weights for a choice-based panel survey sample with attrition

Rising costs associated with conducting surveys, coupled with the need to study infrequent choices, have contributed to a growing interest in and employment of choice-based sampling schemes. More recently, several panel surveys are being conducted in the United States and Europe to measure changes in travel behavior, with a sample much smaller than repeated cross-sectional surveys would require. It is natural to take advantage of these two survey methods and conduct a panel survey with choice-based sampling. In choice-based sampling schemes, where the sample entities are selected based on the endogenous variable under study, the resulting sample will not be representative of the general population. The issue is more complicated with a panel survey because of several possibilities by which choice-based sampling van be conducted over time. This paper shows how appropriate weights can be developed and applied to observations from a choice-based sample so as to draw generalizable inferences. The study is the first attempt to develop weights for a choice-based transportation panel sample. Using a data set from the Puget Sound Region, transitions in discrete travel choice and longitudinal changes in demographic characteristics are inferred.