Roadway Traffic Assessment of the 2023 Maui Wildfires

Abstract

Traffic congestion can be a critical impediment to achieving safe evacuations, especially in the case of short-notice wildfire evacuations. This paper describes a quantitative assessment of traffic movements across the island of Maui, HI, before, during, and after the devastating 2023 wildfires. Traffic counts from the Federal Highway Administration (FHWA) Traffic Monitoring System across Maui were used to reveal where, when, and how much traffic moved on the island, with a particular focus on the Lahaina area. Postdisaster assessments of wildfire events are an invaluable process to learn lessons and improve future planning, preparedness, and response efforts. In this assessment, baseline traffic patterns were established from data collected over five weeks before the fire. Then, data from three weeks during and after the fire were used to identify, quantify, and illustrate patterns of evacuation and reentry. Among the key findings of the work was the difficulty in revealing clear and indisputable patterns of evacuation or reentry out of or into the Lahaina area. This is uniquely different from similar large-scale evacuations in the past, where clear volume patterns typically emerge that show times, directions, and amounts of vehicle movement. It also suggests that evacuees did not travel far, did not travel at all, or moved by modes other than by vehicle in significant numbers. This lack of definitive evidence is both important and useful because, despite more than 100 fatalities and unprecedented levels of destruction, it suggests (1) highly congested and blocked roadway conditions; (2) low situational awareness to make decisions in sufficient time; and/or (3) highly localized transportation impacts. The study also indicates how other data sources need to be considered to capture wildfire evacuation processes to improve infrastructure, operations, and planning.