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 paratransit dispatching task activity in a computer-assisted control room. The dispatching task involves continuous monitoring and interaction with archived and real-time data using a typical dispatch software. Extensive field observations and video recordings of dispatch operations were conducted. Then, a skeleton decision model of the dispatchers activities was generated and later validated with an expert dispatcher. Hierarchical Task Analysis (HTA) was used to further refine this model into a comprehensive HTA decision hierarchy (decision tree). To capture the complexity of multi-dispatcher operation, we extended this model to a simultaneous operation of two collaborative dispatchers in the same control room—a van dispatcher and a lead dispatcher. The results of this analysis showed that HTA could be used to model 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-level dispatch personnel and as a tool for human-computer interaction evaluation in dispatch software design.