Estimated impact of left lane truck restriction on Louisiana highway pavement using MEPDG

Truck lane restriction strategies (TLRS) are strategies used to manage truck traffic on highways by prohibiting trucks from using certain lanes in order to minimize interaction between trucks and other vehicles and currently it is under consideration for implementation in Louisiana’s multi-lane highways. One of the serious impacts of a truck lane restriction on highways is accelerated pavement damage on unrestricted lanes due to the increased truck traffic on them. The purpose of this study is to estimate the increased pavement damage on the right lane in terms of various distress caused by imposing left lane truck restriction on trucks with three or more axles on a six-lane highway section near Lake Charles. Estimating the reduction in life of the pavement caused by introducing TLRS on this section and determining the sensitivity of the input factors were the objectives of this study. The Mechanistic Empirical Pavement Design Guide (MEPDG) software was used to estimate various types of pavement distress expected from the increased traffic on unrestricted right lane after prohibiting trucks from the extreme left lane at the study section. Traffic loading, climatic, and structural data were used as inputs to the model. Data pertaining to vehicle classification was obtained from Weigh-In-Motion (WIM) records and pavement structure information at the study section was collected from the LADOTD. Climatic data for the study section region were available with the software. Because the current truck lane distribution was not known, a total of eight logical truck lane distributions were considered in the study. The MEPDG software was used to simulate “without restriction” and “with restriction at 80 and 90 percent compliance” scenarios for all the truck lane distributions at the calculated annual average daily truck traffic (AADTT) on the study section. Finally, a sensitivity analysis was conducted to predict sensitivity of truck lane restrictions to increased truck traffic and compliance values. Results of this study were then used to determine how much earlier the pavement would fail due to introduction of TLRS. Pavement deformation in the asphalt concrete (AC) layer was the only pavement distress which was found to cause the pavement to fail during the expected life of the pavement, and the pavement failed earlier “with TLRS” than “without TLRS” for all truck lane distributions considered. However, a statistical z test showed no significant difference at the 95 percent significance level between the two values. The decrease in pavement age was not found to be sensitive to the AADTT values considered. The truck lane distribution that produced the greatest reduction in pavement life was the 75-15-10 truck lane distribution, where pavement failure was estimated to occur 9 -10 months earlier “with TLRS’ than “without TLRS” for AADTT values (6206 -8000 trucks per day)