The American Association of State Highway and Transportation Officials (AASHTO) provides the standard framework for this process. Specifically, the 1993 AASHTO Guide for Design of Pavement Structures remains one of the most widely used empirical methods globally.
Where the spreadsheet must solve for iteratively, given: aashto flexible pavement design excel spreadsheet
A database of typical material properties to assist the user in selecting coefficients ($a_i$). The American Association of State Highway and Transportation
For immediate access, the Engineering Community offers a widely used spreadsheet for these calculations. Introduction to AASHTO Flexible Pavement Design aashto flexible pavement design excel spreadsheet
Replaces highly inaccurate paper nomographs with precise, repeatable formulas.
Easy to create tables showing SN vs. ESALs or SN vs. MRcap M sub cap R