'Vehicle Routing', Familiarity and Perturbation in Paramics network

Product Feature: Modeller
Vehicle Routing: All vehicles choose the least cost route between their origin and destination when they enter the model and that this cost varies as the simulation runs (as delay builds up in areas of the network). So the route taken by one vehicle at the start of the simulation may be different to that chosen by another vehicle making the same journey 20 minutes later. Unfamiliar vehicles stick to this initial route choice and do not change their route regardless of changes in cost and delay.

Familiarity: Familiar vehicles (if dynamic feedback is being used with the feedback interval) do change their route depending on changes in delay in the network.

Perturbation represents the fact that not all vehicles will choose the same route between origins and destinations. This is applied by vehicle type so both the familiar and unfamiliar drivers in that type unless there is the population set up such that certain types are 100% familiar and others are 100% unfamiliar and perturbation is applied only to the familiar vehicle types. In addition, other factors can come into play such as link and category cost factors, turning penalties, waypoint routing and fixed routing. For reference when auditing or responding to audits on this topic the best source of info would be the following topics/searches of the Paramics manual:
  • Assignment
  • Vehicle types
  • Configuration
UPDATED:  October 10, 2019