ARB Research Seminar

This page updated June 19, 2013

Identification and Evaluation of Potential Best Practices for Greenhouse Gas Reductions in Freight Transportation

H. Christopher Frey, Ph.D., Department of Civil, Construction and Environmental Engineering, North Carolina State University

January 09, 2008
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA



Freight transportation accounts for approximately 9% of total greenhouse gas (GHG) emissions in the United States. The individual contributions of each of the five freight transportation modes to total freight transportation GHG emissions are 60, 6, 5, 13, and 16 percent for truck, rail, air, water, and pipeline modes, respectively. Energy use for all modes could increase by 75% from 2003 to 2030. We surveyed 59 potential best practices for reducing energy use and GHG emissions in freight transportation. The GHG emissions of interest here are CO2, methane (CH4), and refrigerants.

Over half of the potential best practices are for the truck mode. Reduction in energy use is the basis of GHG emissions reductions for 51 of the potential best practices. The potential best practices are of varying stages of development, with some already proven and others merely concepts. The total estimated GHG emissions reductions by 2025 if all of the potential best practices are aggressively implemented is estimated to be 42% of 2025 GHG emissions compared to if none of the potential best practices are implemented. If all identified potential best practices for the truck mode are implemented aggressively, 2025 GHG emissions could be "reduced" by as much as 28% compared to 2003 levels. Thus, if potential best practices are aggressively implemented, it is possible for there to be a net decrease in total GHG emissions and energy use in freight transportation. Potential additional reductions might be possible if inter-modal shifts are encouraged where possible, such as from trucks to rail. Limited quantitative data is available upon which to base assessments of the costs of potential best practices.

Ongoing work is recommended to obtain or develop cost estimates for best practices for which costs are not reported here, as well as to update cost estimates reported here as new data become available. The impact of variations of key assumptions, such as market penetration rates, fuel prices, capital costs, and operation and maintenance costs, should be assessed via sensitivity analysis. It is critical to develop a decision support framework that will allow parties who might adopt or use a best practice to compare multiple best practices on the basis of site- or situation-specific assumptions. As an example, we are currently engaged in a collaborative field study to evaluate anti-idling technologies for 20 long-haul sleeper cab trucks and in a pilot field study to assess plug-in hybrid diesel technology for a prototype school bus.

Speaker Biography

H. Christopher Frey, Ph.D., is a professor of environmental engineering at North Carolina State University. Dr. Frey's research focuses on: (1) measurement and modeling of real-world activity, fuel use, and emissions of onroad and nonroad vehicles using portable emission measurement systems; (2) modeling and evaluation of advanced technologies for power generation and environmental control; (3) exposure and risk assessment; and (4) systems analysis methodologies, including uncertainty and sensitivity analysis.

Dr. Frey was a lead author for the chapter on uncertainties in the 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories and served in a similar role for the 2005 NARSTO emission inventory assessment. Dr. Frey is a fellow and recent past president of the Society for Risk Analysis. In 2006 Dr. Frey authored a white paper on incorporating risk and uncertainty into the assessment of impacts of global climate change on transportation systems. Dr. Frey has served on numerous advisory panels, such as the Clean Air Scientific Advisory Committee (CASAC) Particulate Matter (PM) Review Panel, a World Health Organization working group on uncertainty in human exposure assessment to chemicals, and the FACA MOVES review group that is advising EPA on the next generation vehicle emissions model. Dr. Frey holds a Ph.D. in Engineering and Public Policy from Carnegie Mellon University.

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