ENVIRONMENTAL IMPACTS OF A MODAL SHIFT

Minnesota Department of Transportation
Ports and Waterways Section

Environmental review is a vital step in the deliberations on the development or improvement of any type of project in the nation’ water, wetlands and floodplain areas. It is necessary for the continued assurance of the quality of such environments. The majority of the analyses conducted in those areas generally concentrates on the possible impacts in the immediate area. And, those analyses are further concentrated by direction only toward biological functions. That is considered most important because of the delicate natural balances that exist.

For certain project proposals, analysis should be expanded to look at additional elements of the environment and to probable impacts beyond the immediate area. This is especially true for projects in the more developed and populated urban commercial/industrial areas. The extension of the analyses should include not only recognition of. biological needs in the area but review of other types of environmental impacts in and beyond the area.

The analysis expansion should be in the direction of a “no build” scenario which is standard for such things as airport, highway and other transportation facility construction or expansion. This type of review is especially important for water transportation projects. An environmental analysis of such a project must look at the environmental impacts which will occur, in addition to the biological ones, if the transportation needs of the project are met by other forms of transportation. Most specifically, what will be the increases in such things as fuel use, exhaust emissions, and probable accidents as well as increased traffic congestion if vessels are replaced by trucks or rail cars. Economic considerations, though important, are not as vital to this type of analysis. To demonstrate the types and levels of impacts expanded environmental review would assess, this study reviewed four commodity movements Minnesota’s river and Great Lakes transportation system. The analysis process involved the development of a “no build” scenario by the theoretic shifting of those cargoes from water to land transportation modes. What was determined in the analysis was that a shift to trucks from vessels would cause:

  • an 826% increase in fuel use annually,
  • a 709% increase in exhaust emissions annually,
  • a 5,967% increase in probable accidents each year,
  • the need to annually dispose of 2,746 used truck tires, and
  • an additional truck traffic load of 1,333 heavy vehicles each day in the study corridors.

In the two corridors where rail is a possible transportation alternative the annual chances with a vessel to rail shift are:

  • fuel use grows by 331% emissions jump by 470%
  • probable accidents grow by 290%

Clearly, those major levels of change show great support for including in the environmental study process the analysis of the damage that can be done to the environment by using a land transportation system to replace a viable water system.