Mechanistic-Empirical Pavement Design Guide (MEPDG) Development and Implementation

Properly designing and accurately predicting performance and durability are critical to improving the design of new and existing pavements. Poor performance increases traffic congestion, compromises public safety, and raises maintenance costs due to frequent repairs. Each year, transportation agencies spend more than $20 billion in Federal funds to improve roadway pavements in the United States.

To improve the design and performance of roadway pavements, ARA, in collaboration with our industry and university teaming partners, developed the MEPDG for adoption and distribution by the American Association of State Highway and Transportation Officials (AASHTO). The MEPDG development occurred under a series of National Cooperative Highway Research Program (NCHRP) studies.

The MEPDG employs mechanistic-empirical approaches that provide a more realistic characterization of in-service pavements and provide uniform guidelines for designing flexible, rigid, and composite pavements. By using these approaches, engineers can create more reliable pavement designs. The MEPDG and its user-oriented software offer procedures for evaluating existing pavements and recommendations for rehabilitation treatments, drainage, and foundation improvements. In addition, the MEPDG incorporates procedures for performing traffic analyses, includes options for calibrating to local conditions, and incorporates measures for design reliability. Engineers can use the guide to analyze common causes of pavement distress, including fatigue, rutting, and thermal cracking in asphalt pavements, and cracking and faulting in concrete pavements.

Because the MEPDG procedure is so different from past, purely empirical procedures, the pavement engineering community recognizes the need for training and assistance to implement and use the new procedure. Many have chosen ARA to provide a variety of products and services to aid in the implementation of the MEPDG, such as:

• A week-long training course that covers a brief introduction to mechanistic-empirical design concepts, the MEPDG procedure, the inputs required and the laboratory tests to be conducted, and agency implementation issues. The course also includes a software workshop in which the participants are given a hands-on training on using the MEPDG software to perform designs for new and rehabilitated rigid and flexible pavements.
• Materials that provide detailed and practical guidance for highway agency personnel to complete a local or regional calibration of the distress prediction models included in the MEPDG software. This assistance includes guidance for confirming and adjusting the global defaults included in the software.
• Pavement design protocols, including testing equipment, testing procedures, traffic input formats, environmental data applications, software issues, and design output interpretation. ARA has also provided training for designers relating to how to use the new design method and accompanying software.
• Local calibration and validation of the MEPDG performance models to ensure that the resulting designs are appropriate for local conditions.

Related

• Pavement Engineering