In 2000, Long-Term Pavement Program (LTPP) continued to play a critical role in the development of the 2002 Guide for Design of New and Rehabilitated Pavement Structures by the National Cooperative Highway Research Program (NCHRP). LTPP data is being used to validate and calibrate performance models for the guide. This is one of the most important elements in developing the guide as it helps demonstrate to the user community that the models/technologies being developed truly match real-world problems. LTPP also launched a pooled-fund study to increase the quality and quantity of monitored traffic data in 2000. The study seeks to obtain the data needed to quantify the relationship between pavement performance and truck volume and axle load. In turn, quantifying this relationship will help the highway community predict the long-term performance of Interstate and other major highways.