At this point, the Equilibrium_Lohse procedure is shown, which serves as the basis of the TributEquilibrium_Lohse procedure and was provided as a separate procedure until the version Visum 2023. The Equilibrium_Lohse procedure was developed by professor Lohse and is described in Schnabel (1997). This procedure models the learning process of road users. Starting with an "all or nothing assignment", drivers consecutively include information gained during their last journey for the next route search. Several shortest routes are searched in an iterative process, where the impedance for the route search is derived from the impedance of the current volume and the last estimated impedance. To do this, the total traffic flow is assigned to the shortest routes found so far for every iteration step. During the first iteration step, only the network impedances in the unloaded network are taken into account (like 100 % best-route assignment). The calculation of the impedance in every further iteration step is carried out using the current mean impedances calculated so far and the impedances resulting from the current volume, i.e. every iteration step n is based on the impedances calculated at n-1. The assignment of the demand matrix to the network corresponds to how many times the route was found ("kept in mind" by Visum).
The succeeding steps in the original Equilibrium_Lohse procedure are illustrated in Illustration 116
Illustration 116: The procedure of Equilibrium_Lohse assignment
