Unpublished preliminary results from the road test were released to the states in 1961
and 1962. The AASHO Interim Guide for Design of Pavement Structures was published
in 1972. Chapter 3 of the interim guide was revised in 1981. The first edition of the
AASHTO Guide for Design of Pavement Structures (1986) introduced many new concepts
including the reliability concept. It was published in two volumes, the first giving
design procedures and the second providing documentation and explanatory information.
The second edition of the guide was published in 1993 and a supplement in 1998.