PERS® allows flexible setup of load types.

In classical use of mechanistic – empirical modelling, all future traffic is combined into one number of standard axle loads (ESALs), and responses are calculated under this load.

Figure 6: Presentation of predicted traffic used in the performance modelling.

Figure 6 shows the graphical representation of traffic data.

With PERS® up to 24 different load types can be defined with their load, axle and wheel configurations, and the damage caused by each load will be considered during the recursive-incremental modelling.

It assumes then that the user has information about the traffic for each defined load type.

A further advantage of the incremental-recursive method is, that the timing of the load repetitions is considered.
There is usually a certain traffic growth rate expected over the analysis period, meaning that an increasing number of traffic loads are distributed over a decreasing strength of the pavement with time.

In this case a standard setup of traffic has been chosen, giving the ESAL used for performance modelling, and the AADT used for user cost calculations.