PAVEXpress is based on calculations from the AASHTO Guide for Design of Pavement Structures 1993 for flexible pavements and AASHTO Guide for Design of Pavement Structures 1998 Supplement for rigid pavements. Since the inception of PAVEXpress, many independent entities have verified the consistency of PAVEXpress to the design recommendations in the respective documents. Below are a couple of recent reports that provide additional validation.