Diesel exhaust from freight trucks is a source of air pollutants, including particulate matter (PM) (such as PM2.5), air toxics, and nitrogen oxide (NOx) emissions (a precursor to ozone). Pollutant emissions related to freight delivery have increased more than 50% since 1990 through increased demand for freight. These comprise close to one-third of the nation’s transportation greenhouse gas emissions, according to the Federal Highway Administration Freight and Air Quality Handbook (FHWA, 2010).
The U.S. Environmental Protection Agency (U. S. EPA) regulates emissions from mobile sources by setting standards for each pollutant being emitted. As these standards become more stringent, the freight industry must devise strategies to meet those requirements. For freight shipped by truck, technological strategies include engine retrofits and use of alternative fuels. Operations strategies include congestion mitigation and idling reduction through specific applications such as weigh station bypass / weigh-in-motion. Research has demonstrated the efficacy of these strategies in reducing emissions.
Additional emissions reductions could be achieved by shipping fewer empty containers. Although freight by rail or water is less emissions intensive, technological and operational opportunities exist for emissions reductions within these modes as well. Air cargo is a small part of freight movement in the United States and its estimated contribution to emissions is small, although relative volumes are anticipated to increase in the future. Intermodal freight transportation with well-connected and coordinated modes is a strategy to optimize use of the transportation network, easing congestion and improving air quality.
Related Transportation and Heath Tool Indicators
How can this strategy result in health benefits?
- Improve equity
- Reduce transportation's contribution to air pollution
How has this worked in practice?
In 2010, the Port Authority of New York and New Jersey partnered with U.S. EPA to provide a financial incentive program to reduce pollution and greenhouse gas emissions. The program would phase out the oldest, most polluting trucks servicing the marine terminals at the Port of New York and New Jersey with newer, cleaner models. The program was open for applications from 2010 to 2013 from qualifying truck-owners. Through the program, the Port Authority disbursing federal grant money to replace 429 older trucks (engine model years 2003 or older) with newer trucks (engine model years 2004 or newer U.S. EPA emissions-compliant engines). The Port Authority also does not allow port drayage (short distance) trucks equipped with engines model year 1993 or older to access the marine terminals. In January 1, 2017, this requirement will be upgraded to engines that meet or exceed model year 2007 federal emissions standards. The Truck Replacement Program is one component of the Clean Air Strategy for the Port of New York and New Jersey. Many other major ports have implemented similar programs.
In 2008, California passed Senate Bill (SB) 375, requiring metropolitan planning organizations to develop Sustainable Communities Strategies with the aim of reducing vehicle miles traveled (VMT) and transportation-related greenhouse gas emissions through alignment of land use, housing, and transportation. To fulfill the requirements of SB 375, The San Francisco Bay Area planned to direct transportation investments to Priority Development Areas identified by local jurisdictions for infill and public transportation-oriented development. Although various health benefits were anticipated for communities in the region, health concerns were also an issue. The Pacific Institute and the Ditching Dirty Diesel Collaboration developed At a Crossroads in Our Region’s Health: Freight Transport and the Future of Community Health in the San Francisco Bay Area in 2011 to assess existing and potential conflicts between freight transport-related land uses and sensitive land uses such as housing, schools, parks, and health clinics in the region. The report used mapping to set health-protective buffers around freight-transport-related land uses, including freeways, rail yards, seaports, airports, warehouses, and distribution centers. It also used mapping to identify sensitive land uses, such as schools, parks, and health clinics, and residentially zoned land within these health-protective distances. A buffer zone distance of 1,000 feet was used around freeways. The report recommends that available suitable land at or beyond the health-protective buffers from freight-related land uses should be prioritized for new housing and sensitive land uses. The report notes that land located with the buffer of freight transport-related land uses be prioritized for commercial and light industrial development.
Where can I learn more?
U.S. EPA’s National Clean Diesel Campaign (NCDC) site includes information on clean diesel technology, emissions reduction projects, grants and funding programs.
Federal Highway Administration (FHWA) Office of Freight Management and Operations’ Freight and Air Quality Handbook provides background on how freight contributes to air quality issues, describes strategies to mitigate freight-related pollutant emissions and improve air quality, and identifies funding and financing tools available for freight-related air quality projects.
The PrePass program site provides information about the nation’s weigh station bypass system.
California Environmental Protection Air Resources Board. Status of Research on Potential Mitigation Concepts to Reduce Exposure to Nearby Traffic Pollution; 2012.
Federal Highway Administration, ICF Consulting. Assessing the Effects of Freight Movement on Air Quality at the National and Regional Level. Washington, DC: U.S. DOT, FHWA; 2005.
Federal Highway Administration. Commercial Motor Vehicle Size and Weight Enforcement in Europe. Washington DC: FHWA; 2007.
Federal Highway Administration. Freight and Air Quality Handbook. Office of Freight Management and Operations; http://www.camsys.com/pubs/fhwahop10024.pdf; 2010.
Federal Highway Administration. Intermodal Freight Transportation. Washington, DC: FHWA, Congestion Mitigation and Air Quality Improvement (CMAQ) Program; 2005.
Greene DL, Baker HH, Plotkin SE. Reducing Greenhouse Gas Emissions from U.S. Transportation. Pew Center on Global Climate Change; 2011.
Lee G, You S, Ritchie S, Saphores J, Sangkapichai M, Jayakrishnan R. Environmental impacts of a major freight corridor: a study of the I-710 in California. University of California Riverside, University of California Transportation Center (UCTC); 2009.
MJ Bradley & Associates. American Lung Association Energy Policy Development: Transportation Background Document; 2011.
Norsworthy M, Craft E. Emissions reduction analysis of voluntary clean truck programs at US ports. Transportation Research Part D; 2013:22:23-27.
U.S. EPA. Health Assessment Document for Diesel Engine Exhaust (Final 2002). Washington, DC: U.S. EPA, Office of Research and Development; 2002.