Disruptive transportation technologies such as shared mobility (e.g., ride-hailing services such as Uber and Lyft), electric vehicles, and connected and autonomous vehicles (in the near future) are positioned to cause large changes in travel demand, which add up to other transformations brought by changes in socio-demographics, individual lifestyles, the increased availability of smartphones and modern communication devices. These changes are transforming travel-related decision making in the population at large, and especially among specific groups such as millennials and the residents of urban areas. This panel study improves the understanding of emerging transportation trends through the application of a unique longitudinal approach. The researchers will analyze the data collected in the 2015 and 2018 waves of the California Mobility Panel, and develop a longitudinal study of emerging transportation trends with a rotating panel structure. The use of longitudinal data will allow researchers to better assess the impacts of lifecycle, periods and generational effects on travel-related choices, and analyze components of travel behavior such as the use of shared mobility among various segments of the population and its impact on vehicle ownership over time. The study will help assess causal relationships behind the observed behaviors and support the development of better-informed policies to promote transportation sustainability.