A public transport system is simulated and integrated on a fine scale with both the traffic simulation and the behavior of the artificial population.

Agents who use transit determine a route to their destination based on the transit schedule. Transit vehicles are moved on the road network in accordance with the traffic flow model, i.e. they may get stuck in congestion and fail to keep their schedule. Agents getting on and off transit vehicles cause realistic delays.

A transport mode decision model is implemented which allows agents to switch their choice of driving a car or using transit based on the relative utility of the two modes. The disutility of travel time, which this model takes into account, is based on actual travel times taken from the simulation.

See the tutorial.  This requires quite some additional input.

Reference

M. Rieser, K. Nagel; Combined agent-based simulation of private car traffic and transit; IATBR 2009