Extended Weight Systems Pavement Analysis

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 coal or coal byproducts were transported by motor vehicles during the previous calendar year. In the past few years, the state has introduced extended weight (EW) systems focused on petroleum products and metal commodities. Trucks can operate above posted weight limits on these networks by paying annual fees that range from $160 to $2,000. While EW networks benefit motor carriers by improving efficiency, vehicles that exceed weight limits can damage pavement and reduce its service life. This study examines the relationship between pavement age and pavement condition on EWCHRS routes 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 that routes which spent at least 20% of the study period on the EWCHRS saw pavement life decline by 1.5 – 2 years. 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. While the future of commodity-specific EW networks in Kentucky is unclear, data management strategies can be adopted by the Kentucky Transportation Cabinet to improve its support of existing and future EW networks