Pseudo-dynamic volumes (PDV)

The pseudo-dynamic volumes (PDV) procedure produces dynamic volumes for each analysis time interval for links, connectors, and (main) turns based on the paths of an existing static assignment and a time series. It is therefore not a dynamic assignment, but a volume procedure.

The dynamic volumes take into account the fact that a vehicle journey does not always end in the same time interval in which it started. The volumes of an analysis time interval thus correspond not only to the corresponding OD demand of this interval but also to the surplus from previous demand intervals, i.e. vehicle journeys that have not yet reached their destination. Thus, the PDV procedure is particularly suitable in the analysis of models with long paths, e.g. national transport models.

Another advantage of the method is the consistency of the volumes, related to the entire analysis period and the individual analysis time intervals: the sum of the volumes of all analysis time intervals is identical to the volumes of the static assignment. Such consistency is usually not achieved in the otherwise standard approach, which is based on assignments per time slot.