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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Social Impact Study


The 2013 study Environmental and Social Impacts of Marine Transport in the Great Lakes-St. Lawrene Seaway Region is designed to provide marine stakeholders, transportation planners and government policy makers with an assessment of the potential environmental and social impacts that could occur, if cargo carried by marine vessels on the Great Lakes-St. Lawrence Seaway navigation system shifted to road and/or rail modes of transport. The study examines the external impacts that can be compared between rail, truck, and vessel, including the following:

  • Fuel efficiency
  • Greenhouse Gas (GHG) emissions
  • Criteria Air Contaminant (CAC) emissions
  • Traffic congestion
  • Infrastructure impacts
  • Noise impacts

The external impacts included in this study are not intended to be an exhaustive list, but rather, represent key impacts common to each of the three surfact transportation modes, enabling comparison. All modes have had historic impacts that are not included in a marginal impact assessment of future traffic shifts.


  • Fuel efficiency: The Seaway-size fleet can move its cargo 24% farther than rail and 531% farther than truck
  • Greenhouse Gas (GHG) emissions: Compared to the Seaway-size fleet carrying one tonne of cargo one kilometer, rail would produce 22% higher GHG emissions and the truck mode 450% higher GHG emissions than marine
  • Criteria Air Contaminant (CAC) emissions: The Seaway-size fleet is primed to realize significant reductions in CAC emissions, including in NOX, SOX, and PM emissions
  • Traffic congestion: A shift to Seaway traffic to highway or rail modes would lead to increased levels of congestion and delays for the traveling public
  • Infrastructure impacts: If Seaway marine shipped cargo shifted to trucks permanently, it would lead to $4.6 billion in additional highway maintenance costs
  • Noise impacts: The noise footprint of Seaway shipping is negligible in comparison with that of other transportation modes

Click to learn more about the Environmental and Social Impacts of Marine Transport in the Great Lakes-St. Lawrence Seaway Region report:

Environmental and Social Impacts of Marine Transport in the Great Lakes-St. Lawrene Seaway Region
Last updated: Thursday, June 12, 2014