Emerging transportation services are quickly changing the way individuals travel by expanding the set of transportation alternatives available for a trip, allowing for more flexibility in travel schedules and providing access to transportation without incurring the costs of auto ownership. One of the most rapidly growing shared-mobility services are ride-hailing services, such as those offered by Uber and Lyft in the U.S. market. In this dissertation, the researcher investigates the factors affecting the adoption and frequency of ride-hailing services and the impacts that these services have on different components of travel behavior using California Millennials Dataset, a rich dataset was collected in fall 2015 with a comprehensive online survey administered to a sample of 2400 California residents, including millennials (i.e. young adults born between 1981 and 1997) and members of the preceding Generation X (i.e. middle-aged adults born between 1965 and 1980).