Transitioning towards the deployment of line-based autonomous buses: Consequences for service frequency and vehicle capacity

Abstract

Abstract The deployment of autonomous buses (AB) is expected to have consequences for service design facilitated by its cost function structure. We study the impacts of AB deployment in line-based public transport (PT) systems. In particular, we examine the transition phase where AB is sequentially deployed, involving the selection of lines for which AB will be introduced. To this end, we develop a modeling framework using a dynamic public transportation assignment and operations simulation model that captures users’ adaptive path choices. An analytical model is used to determine the initial solutions in terms of service frequency and vehicle capacity for the simulation framework. Due to their different cost function structures, the deployment of AB may be accompanied by changes in the service frequency and vehicle capacity settings and consequently also on passenger flow distribution across the network. Both the simultaneous and the sequential deployment of AB on multiple lines are investigated. Deployment solutions are assessed in terms of the both total operator and user cost. The decision variables are vehicle capacity per line, service frequency per line and vehicle technology per line - i.e. either manually driven or fully automated buses. The framework is applied to a case study in Kista, Stockholm. The study shows that AB service have the potential to attract passengers through improved service provision. A sensitivity analysis is carried out concerning the effects of different cost parameters and demand levels on the deployment of AB in fixed line operations.