Cost effectiveness comparison of certain transportation measures to mitigate greenhouse gas emissions in San Diego County, California

California's overarching mandate to achieve 1990 levels of greenhouse gases (GHGs) in 2020 (AB 32, 2005), and the ensuing recent regulations (SB 375, CEQA updates) require local and regional governments to assess GHG mitigation policies, including on-road transportation. The regulations do not make cost-effectiveness a primary criteria for choosing measures but cost remains important to a variety of stakeholders. This communication summarizes results from GHG and cost analysis for seven actual San Diego County road transportation policies: telecommute, vanpools, a bicycle strategy, an increase in mass transit use, parking policies (parking pricing, preferred parking for electric vehicles), an increased local fuel tax and speed harmonization (signal re-timing, roundabouts). Net costs are calculated as the sum of direct costs and benefits to the administering agency, the employer and the individual. Net costs per metric ton GHG abated vary greatly across measures, from negative to high positive (more than US $1000). We find that local GHG cost cannot be sensibly compared to other carbon or GHG policy costs outside the local context for a variety of reasons, but especially because measures have not been adopted primarily for carbon or GHG abatement potential or on the basis of cost effectiveness. (C) 2013 Elsevier Ltd. All rights reserved.