Mapping hazard-access mismatches in wildfire evacuation systems: a multi-facility accessibility framework

Wildfire evacuation depends not only on hazard exposure but on whether residents can reach essential resources under stress. To capture this dimension of evacuation risk across California, the proposed Wildfire Evacuation Resource Index (WERI) quantifies census-tract accessibility to emergency shelters, hospitals, lodging, gas stations, and EV charging stations within a three-step floating catchment area framework, combining proximity, capacity, demand, and competition. A Monte Carlo disruption analysis stress-tests the index under fire-driven road and facility outages, and high-threat low-access tracts are classified by terrain and population density to separate addressable infrastructure gaps from structural geographic constraints. Bivariate Moran’s I links the resulting accessibility patterns to wildfire threat from California’s FRAP dataset. Wildfire threat coincides with high neighboring accessibility for shelter, lodging, gas, and charging, while hospital accessibility shows the inverse pattern. The sharpest mismatches concentrate in Los Angeles for gas and charging, where population outpaces capacity. Between 77 and 86 percent of high-threat low-access tracts for lodging, gas, and charging are in populated communities and are addressable through facility expansion, whereas hospital gaps are largely structural. Population exposure further shows that residents in high-threat areas disproportionately face limited rather than strong access to hospitals, gas stations, and EV charging.