Environment, Planning, and Climate Change Transportation Research Record 2019, Vol. 2673(2) 194–208 Ó National Academy of Sciences: Transportation Research Board 2019 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/0361198118825460 journals.sagepub.com/home/trr Analysis of Transportation Disruptions from Recent Flooding and Volcanic Disasters in Hawai’i Karl Kim 1 , Pradip Pant 1 , Eric Yamashita 1 , and Jiwnath Ghimire 1 Abstract The purpose of this paper is to describe, analyze, and compare disruptions to the transportation system from two recent dis- asters in Hawai’i. While they occurred on different islands (Kaua‘i and Hawai’i) and resulted from different hazards (flooding and volcanic eruption), there are important commonalities due to the disruption of surface transportation and the conse- quences for evacuation and emergency services as well as response and recovery. On Kaua‘i, the physical impacts were fewer, with a 2 mile stretch of highway damaged by flooding and landslides as compared with 31.1miles of roads covered by lava on Hawai‘i island. Both disasters had similar population impacts, with 5,566 people impacted for Kaua‘i and 5,563 for Hawai‘i. Another difference is a shorter duration of disruption and a quicker restoration of transportation services for Kaua‘i com- pared with the slower, continuous, and permanent loss of transportation services in Hawai‘i. The two cases provide learning opportunities for emergency managers, transportation planners, and engineers. Both demonstrate the need for redundancy in transportation infrastructure for rescue and recovery operations. While the evacuation from a flooding event is different than from a slower-moving volcanic crisis, the importance of staging areas, route planning, alternative travel modes, and train- ing cannot be overemphasized. These disasters focus attention on the critical role of transportation systems in response and recovery. In addition to short-term operational actions, longer-term mitigation, adaptation, and risk reduction strategies are needed to support transportation resilience. Natural hazards are physical and environmental phe- nomena caused by slow- or rapid-onset geophysical, hydrological, meteorological, climatological, and biologi- cal events. In this paper, transportation impacts resulting from two natural disasters that occurred in Hawai‘i in 2018 are examined. It focuses on transportation impacts as well as evacuation procedures to move people out of harm’s way. One case involves flooding and the other is a volcanic disaster. This research is motivated by requirements of the National Disaster Preparedness Training Center (NDPTC) (ndptc.hawaii.edu), funded by the US Federal Emergency Management Agency (FEMA) which devel- ops training courses for first responders and emergency managers on disaster preparedness, response, recovery, mitigation, and adaptation. To date, the center has trained more than 39,000 persons across the nation. The research supports course development related to risk and vulnerability assessment, evacuation planning, and disas- ter recovery. While Hawai‘i conjures up images of sway- ing palms and white sandy beaches, it is also a place threatened by volcanoes, earthquakes, tsunamis, hurricanes, flooding, drought, wildfires, sea level rise, and climate change. As an island state, it provides an excellent site to study interactions between transporta- tion and other socio-ecological systems. The disaster on Kaua‘i started on April 14, 2018, with three rounds of intense rainfall and flash flooding. Waip a, on the north shore of Kaua‘i, received a record- breaking 49.69 in. of rainfall over a 24hour period (1). Figure 1 shows the impacted area in north Kaua‘i. The volcanic eruption has been ongoing in the County of Hawai‘i, in the Puna District in the south-east corner of the island. On May 3, 2018, cracks in the roadway began to emerge in the subdivision of Leilani Estates. Initially, steam and gas emerged from the cracks, followed by both P ahoehoe and ‘a‘ a lava flows. P ahoehoe is a basal- tic lava with a smooth, hummocky, or ropy surface that 1 Department of Urban and Regional Planning, University of Hawai‘i at Manoa, Honolulu, HI Corresponding Author: Address correspondence to Pradip Pant: pradip@hawaii.edu