A Hierarchical Task Model for Dispatching in Computer-Assisted Demand-Responsive Paratransit Operation

This research was conducted to organize and model a comprehensive 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 dispatch software. Extensive field observations and video recordings of dispatch operations were conducted. Then, an expert dispatcher was used to generate a skeleton decision model of the dispatcher’s task performance. 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 have shown that HTA can be used to model such an activity with a userdefined degree of fidelity. The sequential decision tree format of the HTA also shows promise as a training tool for entry-level dispatch personnel.