Dynamics of travelers' modality style in the presence of mobility-on-demand services

Modality style -defined as a set of frequent travel modes characterizing the travelers' habits, routines, and predispositions- is a key player in forming dynamics of travelers' mode choice behavior. This study aims to uncover the dynamics of modal preferences while the Mobility-on-Demand (MoD) services operate in the market. Using the 2017 National Household Travel Survey data, a Multiple Discrete Continuous Extreme Value model is developed to analyze the dynamics of individuals' modality style. This model enables us to take into consideration marginal rates of substitutions between different transportation modes. Variables of interest in this analysis include the frequency of use of mobility-on-demand (MoD) services as well as the frequency of walking, biking, transit, and auto trips over the course of a month. The results of this study offer city planners and policymakers an opportunity to better understand the factors underlying modality styles, and which priorities to focus on when designing a sustainable development plan for resident-centric Smart Cities. According to the results, age, work status, education, auto availability, and the built environments are among the significant contributors to the modality styles. The results also indicate that the extent of the substitution relationship between transit and MoD services is highly context dependent.