Guidelines for Evaluating Routine Overweight Truck Routes (0-4184-P2)

The impact of increasing overweight truck loads on Texas highways is a growing concern within the Texas Department of Transportation (TxDOT). Since pavement performance is significantly influenced by the magnitude and frequency of truck traffic loads, guidelines are needed for evaluating the capacity of existing highways to sustain routine overweight truck traffic over a specified performance period. The problem of overweight truck loads has been investigated in related TxDOT projects that led to the development of analysis procedures for evaluating superheavy load routes and load-zoning requirements. Researchers used results from these TxDOT projects to develop pavement evaluation guidelines for routine overweight truck routes that are presented in this report. In this project, researchers developed a two-stage framework that is based on using existing TxDOT capabilities for pavement evaluation, including nondestructive test methods and pavement analysis programs. Level I involves the use of pavement evaluation charts to identify the best possible route from among the alternatives considered and to determine what additional tests and analyses are needed for Level II. It is primarily intended as a screening tool to assist the engineer in identifying candidate overweight truck routes and potential problem areas. Level II involves the application of the Overweight Truck Route Analysis (OTRA) program to evaluate the structural adequacy of an existing route to carry routine overweight truck traffic over the specified performance period. Additionally, OTRA may be used to estimate the thickness of asphalt concrete overlay required to carry the expected number of truck axle loads over the specified design life based on a user-prescribed reliability level. This report presents guidelines on the application of the methodology to evaluate the suitability of using an existing route for routine overweight truck use.