Optimizing Fair Geographic Access to Polling

Abstract

Greater distance to polling sites negatively impacts voter turnout, with minority communities experiencing the most severe effects. Despite this well-documented relationship, election boards and advocacy groups lack effective tools for selecting polling sites that provide equitable access to voting. We address this gap by developing a method that (1) assesses the suitability of a selection of sites and (2) optimally selects a specified number of sites among a set of potential locations. Our novel method employs the Kolm–Pollak equally distributed equivalent—a new metric from the environmental justice literature that was designed to rank distributions of disamenities, such as air pollution, when equity is a concern. This metric allows us to balance minimizing average distance to polls with improving access to those residents that are farthest from polls. It also enables principled comparisons among competing choices of polling sites and across demographic groups given a set of sites. We demonstrate our methods by analyzing early voting locations in DeKalb County, Georgia during the 2020, 2022, and 2024 elections. In particular, we investigate the distribution of the travel burden across demographic groups, how changes in sites between elections impacts those burdens, and how the early voting sites for each election compares to an optimal selection of sites. We also provide specific insight into where the county should seek to add sites and which sites are most critical for serving the community.