The average daily traffic (ADT) or average annual daily traffic (AADT) is an input used for ESAL calculation. Once the AADT is input by the user, the user can specify the percentage of vehicles in 5 different categories under the Load Equivalency Factor window (Calculate LEF). In this window, the percentages of each type of vehicle using the road can be set. However, PAVEXpress does not allow these percentages to vary over the life of the pavement analysis period.