Attributes for the trip chain file, matrices, path file and cost file

Use trip chain file

Trip chain file

*.fkt file with trip chains from a sequence of trips

Matrices

 If this option is selected, Vissim performs dynamic assignment based on one or multiple OD matrices.

• Matrix column: Select number and name of origin-destination matrix (Modeling traffic demand with origin-destination matrices)
• VehComp column: Selecting vehicle composition (Modeling vehicle compositions)

Scale total volume to

Reduce total demand in all origin-destination matrices to the percentage specified in [%] This value is used as a starting point for scaling the total demand of origin-destination matrices by the value Dynamic assignment volume increment (Defining simulation parameters). The starting point value of the reduced total demand increases with each simulation run defined in the simulation parameters (in the Number of runs box) by the Dynamic assignment volume increment until 100 % of the total demand has been reached (Defining simulation parameters).

Evaluation interval

Time interval in which costs are calculated and paths are searched. The path selection of vehicles can change at these intervals. Can be changed, as long as no *.bew cost file has been created (Evaluation interval duration needed to determine the travel times).

Cost file

File with a current list of the costs for the current paths, plus edge times and volumes of the edges of the abstract network graph from the two previous simulation runs (Files of dynamic assignment)

• Check edges: If you edit the Vissim network, numbers of links and edges may change.  If the option has been selected, when reading paths, Vissim checks if the edges from the cost file match the edges in the open Vissim network and tries to replace the edges from the cost file with the current edges in the Vissim network. The check criteria are described in this table at the bottom of section Check criteria for the cost file and path file.

Path file

File with the path archive (Files of dynamic assignment)

• Check edges: If you edit the Vissim network, numbers of links and edges may change.  Select this option to have Vissim check, based on the following criteria, if the edges from the path file match the edges in the open Vissim network and try to replace the edges from the path file with the current edges in the Vissim network.

Vissim criteria to be checked for the cost file and path file:

• Vehicle class or vehicle type not available
• Parking lot not available
• Dynamic dynamic routing decision not available
• Edge not available
• Table Linksanzahl does not contain the origin parking lot
• Table Linksanzahl does not contain the destination parking lot
• Attribute list Edges: attribute Link sequence has no values
• Attribute list Edges: contains nodes that do not exist in the path file or cost file
• Time interval not available
• Values cannot be read because they contain letters instead of numbers
• Not enough entries in a row
• The origin parking lot is not located on the first edge.
• The destination parking lot is not located on the last edge.
• The edges of a path are not connected.

 If this option is selected:

• Before the start of the simulation, Vissim checks whether the following output files are saved in the directory in which the network file *.inpx is saved:
• Path file *.weg
• Cost file *.bew

• Before new output files are generated, Vissim renames the existing output files *.bew and *.weg. When doing so, Vissim adds an underscore and the three-digit number of the simulation run to the file name, for example, Routing_001.weg. If the first simulation run is stared without a path file, there will not be a path file Routing_001.bew.
• Based on the archived files, the changes during dynamic assignment remain traceable. If necessary, you can reset a previous result of an assignment. To do so, replace both the current path file *.weg and the current cost file *.bew with a version of these files that contains the desired, previous results you want to use to run a new simulation. Rename the files, so that Vissim can access them.
• For a simulation with multiple runs, the system checks whether the path file and cost file exist before the start of the first simulation and for every other simulation run (Defining simulation parameters).
• If multiple simulation runs have been defined for the simulation parameter Number of runs, Vissim adds *.bew and *.weg files between the individual simulation runs.

If this option is not selected and in the simulation parameters, in the Number of runs attribute, you have chosen to perform only one simulation run, the existing *.bew and *.weg files are overwritten when the simulation run is performed. If multiple simulation runs have been defined for the simulation parameter Number of runs, Vissim adds the *.bew and *.weg files after the last simulation run and not in between them.

Store costs

 If this option is selected, the specified cost file *.bew is saved.

You may select specific Vehicle classes for which travel times and volumes are saved to the cost file. You can access these vehicle class specific data via the edge attributes and path attributes Travel time (old), Travel time (new), Volume (old) and Volume (new). Then select the subattributes Time Interval and Vehicle Class. The subattribute Vehicle Class is based on the vehicle classes, which were selected here. For each vehicle of a vehicle type that is assigned to a selected vehicle class, vehicle class specific values are used for path search and path selection. Combined with the option Use volume (old) (in the Choice tab), class-independent assignment results of an *.anmroutes file, e.g. exported from PTV Visum, can be reproduced only with stochastic deviation.

Travel times are smoothed based on the smoothing method selected in the Cost tab.

Store paths (and volumes)

 If this option is selected, paths and volumes are saved in the *.weg path file. Next to it, In the Vehicle Classes section, you can select vehicle classes for which additional data, apart from the data for all vehicle classes, is saved to the path file.