THE AASHO ROAD TEST LIVING LEGACY FOR HIGHWAY PAVEMENTS

The American Association of State Highway Officials' (AASHO) Road Test, a major research initiative conducted from 1958 to 1960 near Ottawa, Illinois, continues to influence the pavement and transportation community. The project not only evaluated the performance and behavior of pavement structures under a variety of axle loadings but also investigated the performance of highway bridge structures under known loading conditions, as well as the effects of vehicle cost allocation, military road transport, and more (1-7). The pavement construction, pavement monitoring, and data analysis activities conducted at the Road Test established many standards and protocols and helped define many pavement design, construction, and evaluation practices. Four decades after the completion of the Road Test, the AASHO design procedures remain the cornerstone for both rigid and flexible pavement design in the United States, as well as in other countries. In addition, researchers often use data from the Road Test in a variety of ways unforeseen by the original developers. The approaching 50-year anniversary of the AASHO Road Test construction prompts a look back at the development, features, and characteristics of this major pavement research initiative.