Maximizing space-time accessibility in multi-modal transit networks: an activity-based approach

Over the past decades, the impact of transport operating strategy improvements on space-time accessibility, which is an important research area for network design problem, has not been explicitly investigated particularly with the use of activity-based approach. In this paper, a novel activity-based space-time accessibility measure is introduced for considering individuals’ accessibility to various activities and travels in a unified super-network framework. A bi-level programming model is proposed for optimizing time-dependent transit line headways and fares in a multi-modal transit network from the activity-based space-time accessibility perspective. In the upper level, transit line headways and fares are optimized by time of day to maximize the network-wide activity-based space-time accessibility. At the lower level, an activity-based network equilibrium model is adapted to provide the resultant activity-travel patterns as reactions to the upper level decision. A simplified network in Hong Kong selected area is used to illustrate the application of the proposed model.