A hierarchical task model for dispatching in computer-assisted demand-responsive paratransit operation

This research was conducted to organize and model a comprehensive set of pa ratransit dispatching task activity in a computer-assisted control room. Th e dispatching task involves continuous monitoring and interaction with arch ived and real-time data using a typical dispatch software. Extensive field observations and video recordings of dispatch operations were conducted. Th en, a skeleton decision model of the dispatchers activities was generated a nd later validated with an expert dispatcher. Hierarchical Task Analysis (H TA) was used to further refine this model into a comprehensive HTA decision hierarchy (decision tree). To capture the complexity of multi-dispatcher o peration, we extended this model to a simultaneous operation of two collabo rative dispatchers in the same control room-a van dispatcher and a lead dis patcher. The results of this analysis showed that HTA could be used to mode l such an activity with a high degree of Fidelity. The sequential decision tree format of the HTA also shows promise as a training tool for entry-leve l dispatch personnel and as a tool for human-computer interaction evaluatio n in dispatch software design.