Title: Essays on Aging Americans’ Travel Preferences
Description: The baby boomer generation began turning sixty-five in 2011. Twenty percent of the U.S. population will be over age sixty-five by 2030. Such a rapidly aging population has posed significant challenges to transportation planning and operating agencies since this large number of aging boomers demand dependable transportation access so they can remain independent and age in place. It is crucial to understand, in a timely manner, aging Americans’ travel mode choices, their preferences and perspectives on transportation supports, and communication channels through which they prefer to receive information on existing and new transportation options. My dissertation presents three essays to explore these important and urgent issues. Essay One uses the 2009 National Household Travel Survey (NHTS) data to investigate whether the predominant travel preference—favoring private automobiles—hold for different groups of aging Americans. The analyses not only include the commonly used travel mode choice factors, such as socio-demographics, built environment, and transportation attributes; but also include behavioral aspects such as attitudes towards safety, congestion, public transit, and walking environment.

Results show no evidence that Americans are giving up driving as they age. Therefore, planning as though baby boomers will give up driving private automobiles as they age is not likely to be successful. Results also imply that although it may not be effective for existing seniors, promoting positive attitudes on certain travel options that were otherwise not preferred by middle-aged boomers (e.g., public transit) could be a useful way to encourage this group of boomers to change their future travel mode choices. Essay Two discusses the design and implementation of my own survey on senior transportation options. A comprehensive survey questionnaire is constructed to target various user groups of senior transportation services, including seniors, caregivers and their elderly dependents, and younger individuals. All these respondents represent current or future customers of senior transportation services. The survey is then successfully implemented via the Amazon Mechanical Turk (MTurk) crowdsourcing platform.

Survey data collected from the MTurk platform represents a fairly diversified population; it can capture respondents from different socio-demographic categories, and it shares a similar distribution pattern with the general population data (e.g., U.S. Census) and the large-scale nationwide transportation survey using random sampling method (e.g., NHTS). Essay Three analyzes my MTurk survey data and investigates the impact of behavioral factors derived from the Theory of Planned Behavior (TPB) on travel mode choices among different user groups of senior transportation services. Survey respondents’ preferences on types of senior transportation supports, as well as respondents’ preferable channels from which they want to receive information about senior transportation options, are also examined. Results show attitude factors (e.g., convenience, preference, and independence) in general are perceived as more important drivers for seniors’ mode choices than other aspects of TPB (e.g., social norm, feasibility, and cost).

This indicates more attention should be drawn to attitude factors, rather than the traditional concerns such as feasibility and cost, when designing and implementing interventions on senior transportation services. Compared to the extant literature, this dissertation research reveals a more comprehensive set of the factors that affect aging Americans’ travel mode choices. In particular, it highlights the important role of behavioral factors in seniors’ travel model choices. This dissertation research also demonstrates that Amazon MTurk can serve as a valuable crowdsourcing platform for planning related surveys, experiments, and data collections, especially when addressing timely issues such as aging Americans’ travel needs. It generates useful insights for researchers and practitioners to develop effective policy and service interventions to improve senior’s transportation access, and to address transportation challenges along with the rapid population aging process.