Assessing the Impact of Modal Diversion on Pavement Maintenance Costs and Asset Management Practices

This paper considers the impact of freight modal shifts on pavement life if short line railroads are no longer considered economically viable. The area selected for this case study considers a branch line connecting Ontonagon, Escanaba, and Rousseau, Michigan, which is currently served by the Escanaba Lake Superior Railroad (ELS), to the Green Bay, Wisconsin area. It is anticipated rail traffic will be diverted from Michigan to Green Bay, Wisconsin. The identification of current freight volumes on this rail segment and the corresponding trucking volumes, are estimated, if this rail traffic were diverted to nearby roads. A logistical flow analysis documents the increased truck movements by route if this rail line is lost. The current condition of the highway segments, which would be impacted by the potential line abandonment, is documented in terms of rutting, roughness, faulting, and cracking (alligator, transverse, and longitudinal). The pavement design method currently used by the Michigan Department of Transportation is the 1994 AASHTO Pavement Design Guide and the Wisconsin Department of Transportation uses “WisPave”. These pavement design guides were used to measure the pavements’ ability to handle the additional trucks on the highway in terms of structural number for flexible pavements and thickness for concrete pavements.