This report summarizes research outcomes in an effort to update the California Air Resources Board’s (CARB) current methodology for estimating greenhouse gas (GHG) emission reductions from adding new bicycle paths, lanes, and cycle tracks. At least three programs offer Greenhouse Gas Reduction Fund (GGRF) funding for projects with new bicycle facilities. They include the California Strategic Growth Council’s Affordable Housing and Sustainable Communities (AHSC) Program, the Natural Resources Agency’s Urban Greening Grant Program (Urban Greening) and the California Department of Transportation’s (Caltrans) Active Transportation Program (ATP). To measure GHG emission reductions from new bike paths and lanes, CARB currently relies on a method it published with Caltrans in 2005 for evaluating motor vehicle fee registration projects and congestion mitigation and air quality (CMAQ) improvement projects. The data on which the CMAQ method is based are even older, mostly from the 1990s (see section B of this report). This report reviews the more recent literature to determine whether and how the CMAQ method could be modified—or an alternative method developed—to better reflect emerging data and methods. It also assesses whether the CMAQ method could be expanded to Class III bike boulevards, or to distinguish between Class IV cycle tracks that replace auto travel lanes or parking from those that replace existing Class II bike lanes.
