Navigating Disruptions: Examining Weather-Induced Road Closures and Structural Vulnerabilities in North Carolina’s Road Network

Weather-related road closures have the potential to disrupt society in significant ways. Existing academic literature has already shown that impacts from weather-related road closures can be extreme and affect aspects of societal function like passenger travel and access to essential services. By modifying existing graph theory approaches to analyzing network function to more realistically represent passenger travel, this dissertation examines the function of the North Carolina road network with an interest in impacts caused by weather-related road closures. Using an 8-year archive of historical weather-related road closures across the state, results in Chapter 2 indicate that the state has experienced both acute and cumulative impacts to free-flow travel time from these closures—with rural areas in the state emerging as the most impacted regions. Using a 100-year modeled flood event, Chapter 3 examines road segment-level routing change to local hospitals in rural areas and determines that flood events dramatically change network flow on non-closed roads—increasing concentration on lower-order roads and prioritizing alternative paths not seen in the pre-flood scenario. Finally, Chapter 4 proposes a simple metric to track redundancy (the availability of alternative routes) and applies it to rural census block groups across the state. The results indicate that even among rural areas, which are homogenized in the literature on road network function, there is high variability in redundancy. In total, this dissertation contributes to existing literature by maintaining an analytical focus on rural areas and a methodological focus on improving existing metrics for analyzing road network function using graph theory.