Achieving equitable outcomes through optimal design in the development of microtransit zones

As public transit becomes increasingly personalized with services that can dynamically adapt to demand as it is realized over the course of a day, it is important to ensure that the services are equitable and do not grow on unintended or endemic biases, or create new biases. Such biases might arise from prioritizing cost-effectiveness or system efficiency. This paper explicitly integrates equity considerations in the design of public, microtransit services, i.e., shared-ride public services that typically uses vans or shuttles to move passengers along dynamically generated routes operating within predefined zones. To this end, a mathematical model and solution methodology for designing the microtransit zones with the specific aim of creating equitable services is proposed. Findings from the application of the proposed methodology on a case study of Washington, D.C. showcase how even well-intentioned designs created with equity in mind can result in poor service coverage for the same individuals most in need of a reliable and efficient form of transit. The findings also show that resulting service zones developed from a combination of two forms of equity, horizontal and vertical, exceled in serving Black, Indigenous, and People of Color populations, older adults, and low-income households with only a small reduction in the number of potential riders with services as compared with designs developed from more typical vertical or horizontal equity measures.