Abstract
Temporally integrated bus systems, in which fixed-route services are provided during higher-demand periods and flexible-route services are provided during lower-demand periods, are investigated with analytic optimisation models. Threshold analysis is used to determine which option is preferable for a given demand pattern and to identify favourable situations for integrated operation. Optimised vehicle sizes, route spacings, zone areas, and service headways are obtained and compared for fixed-route, flexible-route, and integrated systems.