Cape Cod Commission’s Adaptation Planning Activities for the Regional Transportation System

The Cape Cod Commission (“Commission”) has begun to systematically consider the long-range impacts of climate change as it works to guide regional transportation- and development-planning efforts for an iconic but vulnerable area of coastal Massachusetts. The Commission is responsible for directing regional land-use policy, regulating developments whose impacts cross town boundaries, and supporting the 15 Cape Cod municipalities that make up Barnstable County with planning and technical expertise.  In connection with these efforts, the Commission conducts regional transportation-planning activities under the guidance of the Cape Cod Metropolitan Planning Organization (“MPO”), which prioritizes federally funded local transportation projects to ensure spending aligns with a regional transportation vision. 

The Commission’s climate-change efforts demonstrate the valuable role MPOs can play in facilitating adaptation planning at a regional scale by coordinating plans and disseminating information.  Since at least 2009, the Commission has published numerous reports and studies that document the climate-driven hazards that will pose an increasing threat to the region’s transportation infrastructure. These studies identify specific vulnerabilities for Commission planners and local officials to consider as they propose future transportation projects.

In its most recent annual work plan, the Commission indicated that it will consider these climate vulnerabilities when planning future transportation-infrastructure improvements and will develop adaptation strategies for existing infrastructure.  The Commission specifically intends to update its Regional Transportation Plan to integrate additional climate-change data; dialog with local officials to monitor at-risk transportation assets and pinpoint areas where resilience could improve; and develop a list of potential climate-change resiliency projects for critical infrastructure.

In the 2016 Regional Transportation Plan (RTP)—a federally mandated 25-year blueprint for future transportation development—the Commission acknowledges that ensuring coastal resiliency by preparing for climate-change impacts is one of most significant challenges and opportunities facing the area.  Adopted in July 2015, the 2016 RTP covers the period from 2016 to 2040.  The RTP notes that Cape Cod is almost completely surrounded by water, rendering its 15 towns highly vulnerable to climate-change impacts such as sea-level rise, storm surge, and flooding. Among its specific adaptation recommendations, the RTP stressed the importance of restoring tidal and freshwater-stream watersheds, particularly where highways cross, to protect natural functions and facilitate water flow during storms.

The RTP documents several of the climate change vulnerability assessments the Commission has conducted to inform the MPO, its planners, and local officials:

  • In 2013, the Commission published a report identifying critical transportation modes and potential vulnerabilities titled “Climate Change Risk and Vulnerability Assessment of Regional Transportation Infrastructure.” To develop the assessment, the Commission used the Federal Highway Administration’s Climate Change and Extreme Weather Vulnerability Assessment Framework (2012).  The report identifies the critical transportation infrastructure (airports, roadways, ferry terminals, marinas and public landings, buses and shuttles, and evacuation routes) and the climate-related hazards that could affect them (hurricanes, sea level rise, winter storms/ Nor’easters, and drought and wildfire). To rank hazards, the Commission relied on its Multi-Hazard Mitigation Plan. The report also recommends  that planners: (1) conduct an assessment of the flooding impact of bridges and culverts that are too small to allow tidal waters to pass completely; (2)  coordinate evacuation route planning at a regional level; (3) review infrastructure surrounding ferries for climate impacts; and (4) plan bus routes based on climate-change vulnerability assessments.
  • In 2015, the Commission published a vulnerability assessment specifically focused on sea-level rise titled “Critical Transportation Assets and Their Vulnerability to Sea Level Rise.” To prepare the assessment, planners (1) developed online maps of all transportation assets and routes; (2) spoke with stakeholders to identify transportation assets deemed critical; (3) measured asset vulnerability using a proprietary sea-level rise viewer that modeled the impacts of 1 to 6 feet of rise in one-foot increments; and (4) generated a list of assets that were both vulnerable and critical to the operation of the transportation network or the social and economic functioning of the area’s towns. The report indicates that air and sea transportation would be significantly affected after only 3-4 feet of sea level rise. Highway, rail, and transit infrastructure would suffer significant impacts with 6 feet of sea level rise.  Planners selected the range of sea-level rise estimates based on the Massachusetts Office of Coastal Zone Management 2013 document Sea Level Rise: Understanding and Applying Trends and Future Scenarios for Analysis and Planning - which projected 0.7 to 6 feet of sea-level rise by 2100.

In addition to citing the Commission’s own vulnerability assessments, the 2016 Regional Transportation Plan documents the value of other federal support in identifying climate vulnerabilities.  In 2009, the Interagency Working Group on Transportation, Land Use, and Climate Change, a 13-agency federal panel assembled by the Federal Highway Administration, selected Cape Cod for a climate-change scenario-planning project.  The project aimed to help planners simultaneously address greenhouse gas emissions and climate change impacts.  As part of the project, the U.S. Department of Transportation’s Volpe Center identified areas vulnerable to climate-change impacts and then incorporated that information into various models for future development trends.  The work helped identify the interrelation of these impacts and other development pressures, land-use policies, potential future development patterns, and transportation needs.   Ultimately, the Commission used this information to help develop the 2016 Regional Transportation Plan to promote development consistent with Cape Cod’s long-term vision for sustainability.

The Commission drew upon varied federal and state data sources to prepare its reports. Among other sources, the Commission used the 2011 Massachusetts Adaptation Plan, which relied on the IPCC 4 report and projected 8 to 16 inches of sea-level rise by 2050, as well as increased hurricane intensity and greater storm frequency and duration throughout the century.  The Commission also used Flood Insurance Rate Maps produced by the Federal Emergency Management Agency (“FEMA”); computerized models developed by FEMA, the Army Corps of Engineers, and the National Weather Service; and the National Oceanic Administration’s Digital Coast sea-level-rise viewer.   The Commission noted the inherent drawbacks of using so-called “bathtub” models, which project inundation based on sea-level rise scenarios without accounting for the incremental changes in coastlines that can occur over time and as the climate changes.


This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on January 29, 2016.


Publication Date: July 2015

Related Organizations:

  • Cape Cod Commission


Resource Category:

Resource Types:

  • Assessment
  • Case study
  • Plans (other)

States Affected:


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