Ph.D. Thesis Defense Announcement

Transportation in an Era of Disruption: How Generational Differences And The New Transportation Technologies Are Influencing Travel Behavior

by

Ali Etezady

Advisor(s):

Dr. Patrica Mokhtarian (GT-CEE), Dr. Giovanni Circella (GT-CEE,UCD-ITS)

Committee Members:

Dr. Kari Watkins (GT-CEE), Dr. Subrajit Guhathakurta (GT-CRP), Dr. Ram Pendyala (ASU-SSEBE)

Date & Time: March 19th, 2021 | 12-2pm EST

Location: http://bit.ly/etezadydefense

 Complete announcement, with abstract, is attached

Over the past decade, the transportation and travel behavior domain has undergone noticeable changes. The emergence of gig and platform economies in conjunction with the rise in sharing economy consumption, largely driven by businesses such as Uber, Lyft, Zipcar or Airbnb, has revolutionized the daily life and mobility of many travelers. In addition, the Millennial generation of travelers has demonstrated different travel habits and patterns compared to their previous generations, with many initial studies showing a decline in driver's license rate, car ownership, and further delay in later life stage events. Together, these two changing forces have also bolstered each other's impact, with the younger generation showing to be a stronger consumer of the sharing and platform economy, giving rise to the expectations that the future of travel might be different than what the current models project. Such prospect, therefore, necessitates a deeper study of these changing forces, whether their impacts last into the future, and how they interact with different aspects of people's mobility.

The main objective of this dissertation, accordingly, is to investigate the impacts of these changing patterns on transportation-related attitudes and behaviors. More specifically, this dissertation first examines how the attitudes of Millennials – currently the largest demographic in the U.S. – differ from those of the previous generation and identifies the driving forces shaping these differences, in addition to how the influence of those forces is likely to change millennials' attitudes over time. We observe that although the attitudinal differences between Millennials and Gen Xers are fairly modest, Millennials' attitudes are closer to those of Generation X as they gain on a host of life-stage variables such as marital status, income, and education. Subsequently, this work investigates the travel mode impacts of ridehailing services, how their impacts differ across latent demographic cohorts, and more specifically, how shared (pooled) rides and their adoption and usage patterns are different by the identified latent cohorts. We find that the younger class of ridehailers have the highest adoption rate and usage frequency of shared ridehailing and conclude that 30% of the total shared ridehailing adopters in our sample, and 50% of the frequent users (weekly users), are associated with the class of ridehailing modal impacts where transit and taxi are impacted the most. This dissertation further investigates another important aspect of ridehailing services: their interaction with current vehicle ownership decisions and future intentions to change this important household commodity. Acknowledging that such relationship is subject to heterogeneity in the population with respect to factors such as age and attitude, we present a detailed picture of how the factors influencing these decisions and their interactions vary across different latent population cohorts.

This dissertation contributes to the literature not only by furthering the knowledge on the concurrent role of generational cohorts and emerging transportation technologies in shaping the future of travel, but also by introducing new methodologies to the field of travel behavior research. Ultimately, the outcomes of this dissertation can help inform travel demand models, public transit agencies, private ridehailing companies, and transportation equity causes, while the new methodologies can help bring new insights in other areas of transportation research.