Chattanooga-Hamilton County/North Georgia 2040 Regional Transportation Plan

The long-range regional transportation plan for the Chattanooga-Hamilton County/North Georgia Transportation Planning Organization (CHCNGA TPO), entitled “2040 Regional Transportation Plan” (2040 RTP), includes a report on Climate Change and Transportation Resiliency for the region. The Plan identifies critical transportation assets in the CHCNGA TPO region, assesses the potential vulnerability and risk for each asset across a range of potential impacts, and outlines planning, design and operations adaptation actions that could be deployed to mitigate potential vulnerabilities. All projects considered for funding in the 2040 RTP were evaluated on how they would impact the critical assets.

The report for 2040 RTP on Climate Change and Transportation Resiliency in the CHCRPA Region was developed following a one-day Climate Adaptation Workshop with infrastructure experts. It leverages data on past extreme weather events, future climate projections, and transportation attributes and applies on-the-ground insights of practitioners to conduct an assessment of potential vulnerability and risk for critical transportation assets across a range of potential impacts. Three of the critical transportation assets were analyzed in more detail by identifying stressors that make the assets vulnerable, potential impacts and consequences to the transportation system, and potential adaptation strategies to reduce impacts. For example, for the I-75/I-24 Interchange asset, extreme temperature could result in slight or significant pavement expansion, which could cause varying levels of service disruption and damage to the Interchange. Alternative route planning and pavement improvements are suggested as adaptation strategies to minimize these impacts. The report also presents a range of adaptation strategies, organized by climate-related impacts and stage of project implementation (planning, design, or operations), that can be applied to a broader range of transportation assets in the region. The strategies identified in the report are intended to serve as a foundation for the ongoing discussion of transportation-related climate change adaptation in the CHCNGA TPO region.

The critical transportation assets defined in the report were also utilized in 2040 RTP’s transportation security analysis, which considers events that may affect the security of the region’s transportation system. All projects considered for funding in the 2040 RTP were screened against the previously-identified five critical assets to determine if the proposed project enhanced an evacuation route and/or provided additional capacity in proximity to the asset. Projects that were deemed to enhance an evacuation route or provide additional capacity in proximity to the asset were assigned additional points during the project evaluation process.

Prior to the workshop and transportation vulnerability assessment, the project team of consultants generated original projections that incorporated regional information on extreme precipitation and extreme temperature. Using original projections instead of existing projections, which generally focus on climate averages, allowed the project team to assess vulnerability to weather extremes that pose the greatest risks to infrastructure. The Chattanooga region experiences heavy precipitation, extreme temperatures, droughts, winter storms, thunderstorms, and tornadoes; the vulnerability assessment focused on hazards related to increasing precipitation and temperature extremes because they are likely to have the most significant impacts on infrastructure. The project team performed statistical downscaling from general circulation models (GCMs) to achieve a better regional spatial resolution for conducting impacts analysis. The team used historical precipitation data from the National Climate Assessment Southeast Region Technical report, and performed regional precipitation projections to estimate future conditions, which project increasing frequency of the current 50- and 100-year 24-hour rainfall events. For temperature projections, the team used previous temperature data from the Global Historical Climatology Network Daily at Lovell Airport and developed projections, which indicate a continued trend for increasing annual average days with extreme heat.

 

This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on February 3, 2015.

 

Publication Date: December 2013

Related Organizations:

  • Chattanooga-Hamilton County/North Georgia Transportation Planning Organization

Sectors:

Resource Category:

Resource Types:

  • Plans (other)

States Affected:

Impacts:

  • Air temperature
  • Precipitation changes

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