Modelling joint activity-travel pattern scheduling problem in multi-modal transit networks

Over the past decades, many activity-based travel behaviour models have been proposed based on individuals’ independent decision making. The modelling of individuals’ joint activity/travel choices, however, has received less attention. In reality, both independent and joint activities/travels form individual’s normal daily activity-travel patterns. Travel surveys have indicated that joint activity/travel constitutes an important part in individuals’ daily activity-travel patterns. On this basis, explicit modelling of joint activity/travel choices is an essential component for long-term transport planning. In this study, an activity-based network equilibrium model is proposed for scheduling two-individual joint activity-travel patterns (JATPs) in congested multi-modal transit networks. The proposed model can be used to comprehensively investigate individuals’ activity choices (e.g. activity start time and duration, activity sequence) and travel choices (e.g. departure time, route and mode) in multi-modal transit networks, including both independent ones and joint ones. The time-dependent JATP choice problem is converted into an equivalent static user equilibrium model by constructing a joint-activity-time-space (JATS) super-network platform. Joint travel benefit is modelled by incorporating a commonality factor in the JATP utility. A solution algorithm without prior JATP enumeration is proposed to solve the JATP scheduling problem on the JATS super-network. Numerical results show that individuals’ independent and joint activity/travel choices can be simultaneously investigated by the proposed model. The impacts of joint travel benefit on individuals’ independent and joint activity-travel choices are explicitly investigated.