At the nexus of equity and transportation modeling: Assessing accessibility through the Individual Experienced Utility-Based Synthesis (INEXUS) metric

We propose the Individual Experienced Utility-Based Synthesis (INEXUS) accessibility metric, which is developed to leverage an open-source agent-based regional transportation model. We include two specifications: the Potential INEXUS, which relates to an individual's potential set of mode alternatives and the Realized INEXUS, which reflects the optimal mode chosen by the agent. One advantage of using an agent-based approach is that it enables us to estimate individual agent-level behavior and travel needs. This addresses a commonly identified limitation of many existing accessibility metrics, which exhibit insensitivity to the heterogeneity of transportation preferences, opportunities, and constraints across subpopulations. While many system-level outcomes of interest may inform transportation planning, arguably an equally important consideration is that the system provides adequate and equitable access to goods and services for the broad spectrum of those traveling along its network. In many cases, average results do not reflect the experience of a majority – or even a significant – portion of the population. We apply our methods in a case study of alternative ridehail price scenarios to demonstrate the value of INEXUS distributions in evaluating differences in accessibility within and between population groups.