Cost-Effective Approaches to Reduce Greenhouse Gas Emissions Through Public Transportation in Los Angeles, California

Document Type

Journal Article

Publication Date


Subject Area

place - north america, technology - emissions, planning - environmental impact, mode - subway/metro


Greenhouse gas emissions (GHG), reductions, cost-effective reductions, transit-oriented development, vanpool subsidy


The Los Angeles County, California, Metropolitan Transportation Authority (Metro) commissioned a study of strategic options for the agency to reduce greenhouse gas (GHG) emissions. This study compared a comprehensive range of strategies on potential GHG reductions and cost-effectiveness, in dollars per ton of GHG emissions reduced. Sixteen strategies were analyzed in four categories: promotion of alternative travel modes, transit service, vehicle technology, and facility energy use. Strategies with the greatest potential for GHG emission reductions (regardless of cost) included transit-oriented development, vanpool subsidy, onboard railcar energy storage, and ridesharing and transit programs for employers. The first three would save or generate money for Metro. Ridesharing and transit programs have the potential for net revenue generation, but the results were uncertain. Four more strategies would reduce smaller amounts of emissions while also saving money for the agency: recycled water for bus washing, low-water sanitary fixtures, Red Line tunnel lighting retrofits, and facility lighting efficiency. Understanding opportunities for GHG reductions requires expertise in transit operations, vehicles, facilities, and planning. Cost-effectiveness and total reduction potential can be supporting criteria in making funding decisions. The largest GHG reduction opportunities for Metro are typically those that reduce vehicle miles traveled, whereas many of the most cost-effective strategies address GHG emissions from facility energy use. Cost-effectiveness of a strategy to Metro can depend greatly on receipt of external funding, including federal funds or utility rebates. In some cases, the range of cost-effectiveness for a strategy is so great that it is not useful to inform decision making without some further definition.


Permission to publish the abstract has been given by Transportation Research Board, Washington, copyright remains with them.