Optimizing Paratransit for Use in Two-Stage Transit-Based Evacuations

Planning for a transit-based evacuation presents many challenges for planners, particularly due to resource limitations. These limitations make it crucial to optimize the use of available transit vehicles. This study introduces the Paratransit- Transit Pick-Up and Delivery Problem (PTPDP), a variant of the traditional vehicle routing problem, designed to optimize the routing of available paratransit vehicles in a two-stage transit-based evacuation scenario. The PTPDP targets evacuation assistance at elderly, mobility-impaired, and homebound evacuees that are especially disadvantaged in this scenario type and uses paratransit vehicles to transport them from their individual locations to bus stops for further evacuation. The model uses a multi-objective approach that minimizes the initial wait time of evacuees, the travel time of paratransit vehicles, and the wait time of evacuees at bus stops for buses to arrive. VISSIM simulation software is used to collect input data for the model. This study applies the PTPDP model to a hypothetical evacuation scenario for the Virginia Tech campus and its surrounding areas in Blacksburg, Virginia to demonstrate the applicability of the PTPDP model.