Determining Fair Share Regional Targets for Reduction of Greenhouse Gas Emissions from Transportation and Land Use

California passed landmark planning legislation, Senate Bill (S.B.) 375, in 2008, calling on the state's urban regions to reduce greenhouse gas emissions through more efficient transportation and land use. During 2010, the California Air Resources Board worked with the state's 18 metropolitan planning organizations to define and adopt performance targets for emissions reductions in each region according to S.B. 375. This target-setting process represents the first systematic effort by a U.S. state to assess the impacts of existing regional transportation and land use plans on greenhouse gas emissions and to adopt specific, realizable alternative scenarios in furtherance of state climate policy goals. This paper considers the technical and political challenges of defining the performance targets across regions and agencies with different conditions and capabilities. The paper depicts the S.B. 375 target-setting process as inherently political and collaborative. The paper also presents analysis from the target-setting documentation. Scenarios modeled to achieve emissions reductions in California's largest urban regions indicate that the greatest benefits are possible through combining pricing and land use strategies. The findings will inform policy makers in other states who also seek to address climate change systematically through coordinated transportation and land use strategies.