Hawaii Highways Climate Adaption Action Plan

Highways in Hawai‘i are surrounded by water and crisscross rugged volcanic island terrain. As such, the infrastructure that island residents depend on is exposed to a variety of hazards, which are only increasing in frequency and intensity with a changing climate.

Sea level rise, coastal erosion, extreme temperature fluctuations, wildfires, intensifying storms and more frequent landslides and rockfalls from heavy precipitation all threaten that critical infrastructure. These, and other more unique and localized risks such as tsunamis and lava flow, can have significant impact on the islands’ transportation networks, and in turn life safety, mobility and economy.

Recognizing the need to proactively address these hazards and prepare its infrastructure for a dynamic future, the Hawai‘i Department of Transportation (HDOT) partnered with WSP to develop the Hawai‘i Highways Climate Adaption Action Plan: Strategies for a More Resilient Future, as well as a companion report documenting the assessments that determine the exposure of Hawai‘i highways to multiple hazards.

The Action Plan serves multiple important functions: it helps define the extent and timeframe of changing conditions; it identifies specific locations along HDOT’s 971 miles of highway and associated assets that are exposed to climate-related hazards; and it suggests changes to HDOT policies and practices to better incorporate resilience thinking into agency decision making and infrastructure investment. A living document, the Action Plan also prioritizes recommendations in a multi-year Implementation Plan to take necessary projects from planning to construction.

The accompanying Exposure Assessment Report details the specific miles or units and percentage of assets — roads, bridges, culverts and tunnels — vulnerable to the threat of natural hazards and the degree to which they may be exposed. Analysis of the data indicates that of all HDOT’s assets across six islands, 58 percent of the network is exposed to potential climate stressors and lava flows, including 303 bridges, 48 culverts and 6 tunnels. The report includes recommendations to improve data, conduct follow-up analyses, strengthen partnerships, and establish asset-focused evaluation programs, among other technical recommendations.

To develop the reports, WSP performed extensive research on present and anticipated hazard conditions and existing infrastructure, compiling a georeferenced highway asset inventory using HDOT data and state-of-the-art information systems. This peer-reviewed research included interviewing and working with local and technical experts from HDOT, the University of Hawai‘i at Mānoa, the University at Albany, the United States Geological Survey, and the Federal Highway Administration. The report includes the most of up to date data and literature resources available for Hawai‘i and establishes a baseline that can be used as the foundation for a climate and disaster risk assessment.