Travel by sustainable modes such as public transit, biking, and walking provides positive outcomes for urban residents for the environment and health. Integrating these mode choices into regular travel trips has been challenging for many Americans. The low adoption of sustainable travel modes has been attributed to environmental factors, and to attitudinal and habitual tendencies rooted in an individual’s beliefs and experiences. The proposed project focuses on understanding the decision-making process of travel mode choices for non-commuting trips. It addresses the policy issue of how to increase usage of sustainable travel modes for those trips through environmental and psychological approaches. At the center of this study are two research questions: 1. What are the barriers to urban residents’ adoption of sustainable travel modes for non-commuting trips? 2. What are the factors and processes that help mitigate those barriers’ influences on individuals’ choice of a sustainable travel mode? We build on a survey deployed during the COVID-19 lockdown in the Eugene-Springfield, Oregon region to implement a mixed-method, longitudinal study. We treat the significant transportation disruption induced by the COVID-19 lockdown as an intervention. We examine: 1. changes in people’s travel mode choices as a reaction to the intervention; 2. changes in cognitive/psychological status in relation to the travel behavior change and the intervention; and 3. the combined effects of environmental and cognitive/psychological factors on people’s desire and reasons to maintain or suspend those behavior changes post intervention. Knowledge and insights gained from this project will contribute to our ability to understand and estimate future sustainable travel behavior, as well as inform infrastructure investment decisions and transportation demand management programming that deploy interventions related to both environmental and psychological dimensions.