The AASHTO flexible pavement design method is based on the following equation:
An Excel spreadsheet can be a great tool for implementing the AASHTO flexible pavement design equations and calculations. Here's a helpful post on the topic: aashto flexible pavement design excel spreadsheet
For those who may not be familiar, AASHTO (American Association of State Highway and Transportation Officials) provides guidelines for flexible pavement design, which is a widely used method for designing pavement structures. The AASHTO flexible pavement design method is based