How is online shopping reshaping activity patterns? Modeling activity behavior using discrete continuous models

This paper investigates how the rise of online shopping has reconfigured daily time–use patterns across six activity categories (online shopping, in–store shopping, at–home leisure, outside–of–home leisure, at–home maintenance, and outside–of–home maintenance) using the 2013 and 2023 waves of the American Time Use Survey. We employ a multiple discrete continuous framework to jointly estimate time–allocation parameters, decade-shift effects, and to capture complementarity and substitution effects among virtual and non–virtual, home–based and outside–of–home pursuits. Our results reveal that, while baseline shopping preferences remained stable over the decade, participation in at–home leisure and maintenance rose sharply and outside–of–home engagement declined, a likely legacy of pandemic confinement and shifting consumer expectations. Interaction effects show that online shopping complements in–store shopping and at-home leisure but substitutes for outside–of–home leisure and any type of maintenance activity. These findings highlight the need for activity-based travel demand models that more explicitly incorporate at-home and ICT-mediated behaviors, as well as for transportation and access policies that respond to the changing relationships among online shopping, in-store shopping, freight activity, and daily time use across different household and neighborhood contexts.