This tool calculates the required SN. The Provided SN depends on
whether this is new construction or a rehabilitation.
Please see the AASHTO 1993 Pavement Design Guide for guidance
on rehabilitation design as well as calculations for ESALs.
Please note that the structural coefficient of the base layer (0.34) is a function of its position
within the pavement structure and not necessarily material properties. It was derived from
empirical relationships at the AASHTO Road Test and therefore a hot-mix-asphalt base should
be considered at 0.34 per inch and not 0.44 per inch.