Departure Time Choice and Bottleneck Congestion with Automated Vehicles: Role of On-board Activities

The enhanced possibility to perform non-driving activities in automated vehicles (AVs) may not only decrease the disutility of travel, but also change the AV users’ departure time preferences, thereby affecting traffic congestion. Depending on the AV interior, travellers may be able to perform in the vehicle activities that they would otherwise perform at home or at work. These possibilities might make them depart at different times compared to situations, when they are not able to engage in any activities during travel or when the possible activities do not substitute any out-of-vehicle activities. This paper formalises the on-board activity and substitution effects using new scheduling preferences in the morning commute context. The new scheduling preferences are used (1) to analyse the optimal departure times when there is no congestion, and (2) to obtain the equilibrium congestion patterns in a bottleneck setting. If there is no congestion, it is predicted that AV users would choose to depart earlier (later), if the on-board environment is better suited for their home (work) activities. If there is congestion, more AV users departing earlier or later would skew the congestion in the corresponding direction. Given the minimalistic bottleneck setting, it is found that congestion with AVs is more severe than with conventional vehicles. If AVs were specialised to support only home, only work, or both home and work activities, and would do so to a similar extent, then ‘Work AVs’ would increase the congestion the least.