Environmental Impact Report in San Francisco Bay Area Transportation 2035 Plan: Change in Motion

The Metropolitan Transportation Commission (MTC) completed an Environmental Impact Report (EIR) In order to assess the impacts of proposed transportation investments in the San Francisco Bay Area. The EIR includes a qualitative assessment of potential climate change impacts on the region’s transportation system, with a focus on sea-level rise impacts. It also suggests measures to protect transportation assets from the impacts of climate change. The EIR, finalized in 2009, was part of the development of the MTC’s long-range transportation plan, “Transportation 2035 Plan: Change in Motion." That Plan outlines a program of infrastructure investments totaling $218 billion over 25 years in the nine-county Bay Area. The Plan also includes a “Transportation Climate Action Campaign” to reduce transportation-related GHG emissions.

The EIR identifies climate change as one of a number of “issue areas of concern” that could affect transportation investments proposed in the Plan. Under this heading, the EIR assesses both opportunities to reduce GHG emissions and the potential impact of climate change on the transportation network in the region. The EIR cites climate change impacts in California identified by the California Climate Action Team, including sea-level rise, increased storm surge, increased erosion, and coastal inundation. In particular, the EIR qualitatively assesses the potential effects of sea-level rise on the regional transportation system as a whole. The EIR uses estimates of local sea-level rise developed by the San Francisco Bay Conservation and Development Commission (BCDC) to identify areas threatened by sea-level rise and storm surge in the period 2040-2060. Threatened transportation assets include 99 miles of major roads and highways, 70 miles of rail corridor, and 72% of the land area of the San Francisco and Oakland airports.

The EIR provides only a qualitative assessment of the impact of sea-level rise on the proposed projects included in the Plan. The EIR distinguishes between the risk to the current system and the additional risk presented by future climate change impacts to the proposed projects. Because the current transportation system is already at risk, the EIR finds that the additional risk presented by future sea-level rise is not significant. However, the EIR acknowledges that the impact of climate change may become cumulatively significant if population growth and development patterns lead to an increase in population and development in areas more vulnerable to sea-level rise. The EIR also suggests that measures taken to reduce the vulnerability of infrastructure to sea-level rise may contribute to climate change by increasing GHG emissions from construction. In sum, the EIR finds that although sea-level rise is likely to impact the region’s transportation network, the proposed projects do not significantly increase that risk.

The EIR identifies a number of measures that could be implemented to reduce the vulnerability of the transportation system to sea-level rise, including planning for infrastructure protection, investing in vulnerability analyses, and exploring the potential for realigning infrastructure. Specific adaptation measures included in the proposed Plan include funding research to evaluate areas at risk from sea-level rise and developing recommendations to guide policy and to help decision-makers develop land-use plans for areas vulnerable to sea-level rise. The MTC proposes to work in partnership with BCDC to conduct a vulnerability assessment for the region’s transportation infrastructure. The EIR also suggests that environmental review documents for individual projects include consideration of measures to reduce impacts to the regional transportation system from sea-level rise and storm surge.

The analysis in the EIR finds that the risk to the transportation network from sea-level rise will increase in the future. However, all of the alternatives considered in the EIR reduce the vulnerability of the system to sea-level rise when compared to the “no project alternative." The transportation projects included in the Plan, like developing hundreds of miles of express toll lanes, increasing bus service, and expanding bicycle infrastructure, are designed to improve the function of the transportation network. Compared to the no project alternative, these proposed projects are also expected to reduce the vulnerability of the transportation network to climate impacts by reducing congestion and increasing connectivity, which will allow the system to better cope with localized storm surge inundation.

In 2013, MTC and the Association of Bay Area Governments (ABAG) released “Plan Bay Area,” an updated regional transportation plan combined with the region’s first Sustainable Communities Strategy as required by state law. MTC also completed an EIR as part of the development of Plan Bay Area; the Plan Bay Area EIR contains a climate change and greenhouse gas emissions chapter that discusses the proposed land use and transportation plan could affect emissions and how sea-level rise might impact the transportation investments proposed.

MTC and ABAG finalized and adopted this integrated land use and transportation plan in 2017, as Plan Bay Area 2040 .


This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on March 21, 2016.


Publication Date: April 2009

Related Organizations:

  • California Metropolitan Transportation Commission (MTC)


Resource Category:

Resource Types:

  • Assessment
  • Plans (other)

States Affected:


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