• Assign

Assignment Tools#

duaIterate.py#

"duaIterate.py" helps you to perform the computation of a dynamic user assignment (DUA). It works by alternatingly running the simulation to discover travel times and then assigning alternative routes to some of the vehicles according to these travel times. This is repeated for a defined number of iteration steps. At least two files have to be given as input the script: a SUMO network and a set of trip definitions. A stochastic user-equilibrium (UE)traffic state is not guaranteed after the assignment. Increasing the number of iteration steps increases the likelihood of convergence to equilibrium.

Within each iteration step, the script generates a configuration file for the duarouter application and starts it with this configuration file. Then, a configuration file for sumo is built and sumo is started. Both configuration files are completely defined within the script itself. As default, for each time step, SUMO will generate three dump files with edge-dumps aggregated over 150, 300, and 900s, a summary information as well as a trip information output. The names of these outputs are numbered according to the iteration step. If you want to change the outputs, you also have to take a look into the script, but you should not disable the edge-based dump for aggregation over 900s, because this is read by the duarouter in the next iteration steps in order to compute the DUA.

For further options of the script either look at the source code or start it with the "--help" option.

python tools/assign/duaIterate.py -n <PATH_TO_SUMO_NET> -t <PATH_TO_TRIPS>

Loading vehicle types from an additional file#

If the file vtypes.add.xml defines vehicle types that are needed by the traffic demand input for duaIterate.py, the following options must be set

--additional vtypes.add.xml duarouter--vtype-output dummy.xml duarouter--additional-files vtypes.add.xml

The first option passes its arguments only to the sumo process. The other options are passed to duarouter and ensure that the types are read but are not written to the route output file (since they would then be loaded twice by sumo resulting in an error).

duaIterateMix.py#

This tool is designed to solve the multiclass traffic assignment problem for mixed traffic flow. Most of the options in this tool are similar to those in duaIterate.py, with a few exceptions. To solve the multiclass traffic assignment problem, you need to provide two demand files. Use the option -t to specify the demand for UE-seeking vehicles, and use the option -r to specify the demand for SO-seeking vehicles. To obtain the multiclass traffic assignment solution, you should set the following options: --mix, --marginal-cost, and --marginal-cost.exp.

duaIterate_analysis.py#

To check the evolution of different simulation parameters during the dua estimation an additional script is provided which analyses teleport counts and how they evolve over the iterations.

python tools/assign/duaIterate_analysis.py dualog.txt

cadytsIterate.py#

This script is a variant of duaIterate.py which uses the Cadyts calibration tool, developed by Gunnar Flötteröd at EPFL, Switzerland. With this script, route choices will be adjusted according to given link counts. The validation work of the calibration between SUMO and Cadyts is work in progress. You will need to download Cadyts separately and add a reference to the jar file to the call.

python tools/assign/cadytsIterate.py -n input_net.net.xml -r routes.rou.xml -d input_measurements.xml --classpath cadyts.jar

one-shot.py#

The one-shot.py provides a variant of the dynamic user assignment. The assignment method is the same one which SUMO and the dua-iterate.py use. Given trips will be assigned to respective fastest routes according to their departure times and a given travel-time updating interval. Different travel-time updating intervals can be defined by users, such as 900, i.e. link travel times will be updated every 900 sec. If the travel-time updating interval is set to -1, link travel times will not updated and link trave times at free-flow speeds are used for all trips.

A stochastic user-equilibrium traffic state will not achieved with the use of this script.

An exemplary execution command is shown below.

 one-shot.py -f <travel-time updating interval> -n <network file> -t <trip file>

 where -f travel-time updating interval (sec); -1 means no travel-time updating (default: -1,1800,300,15)
       -n network file name and the respective path
       -t trip file name and the respective path

Additional setting, such as outputs of summary and trip-information as well as begin time, could be made by adding respective options which can be found in the script.

matrixDailyToHourly.py#

This script is to generate hourly matrices from a VISUM daily matrix. The traffic demand of the traffic zones, which have the same connection links, will be integrated. The exemplary command is indicated below.

matrixDailyToHourly.py -m <matrix file> -z <district file> -t <flow time-series file> -o

<output directory>

where -m: matrix file name
      -z: district file name
      -t: name of the file containing traffic flow time series (optional); If not specified, the defined
          daily matrix will be regularly divided into 24 hours.
      -o: output directory name and the respective path

costFunctionChecker.py#

Run duarouter repeatedly and simulate weight changes via a cost function. (to be continued)

Still under construction!