Extended Weight Systems Pavement Analysis

Abstract

Kentucky established its Extended Weight Coal or Coal By-products Haul Road System (EWCHRS) in 1986. This road network includes segments of the Coal Haul Highway System on which more than 50,000 tons of coal or coal byproducts were transported by motor vehicles during the previous calendar year. In the last few years, the state has introduced extended weight (EW) systems that focus on petroleum products and metal commodities. Trucks can operate above posted weight limits on these networks by paying an annual fee ranging from $160 to 2,000. Although EW networks benefit motor carriers by improving efficiency, vehicles that exceed the weight limits can damage pavement and reduce its service life. This study examined the relationship between pavement age and condition on EWCHRS and non-EWCHRS routes to understand the implications of EW networks for infrastructure life-cycles. Using data from 2008 through 2020 (with the exception of 2016) to perform regression analysis, researchers found routes that spent at least 20% of the study period on the EWCHRS saw pavement life decline by 1.4 to 2 years over an average 12-year life cycle. In general, a positive correlation was observed between exposure on the EWCHRS and loss of pavement life, which can increase maintenance, repair, and rehabilitation costs.