What is the Route cost calculation formula from using DUA router? I've gotten routes(adjacent edges connected) from setting TAZ(O-D matrix) in DUA router, but cannot interpret how routes of each vehicles are formed. I assume it's mainly by travel time and congestion level. If I cannot know the exact Route cost calculation formula, what are the main factors of it?
Are there a tool for assigning routes based on the simulation's congestion? If the routes are defined by the fastest route by DUA router, and if the results are same for each entry direction, congestion will happen after all. I tried dualterate.py, but keep getting errors. I used the same input xml files for DUArouter configuration. I assume there is Automatic Routing(https://sumo.dlr.de/docs/Demand/Automatic_Routing.html), but it I guess my network is just one signalized intersection, so I might try at a bigger intersection.
*Made one signalized intersection in SUMO netedit and running with different cases in SUMO cfg
By default duarouter uses travel time on the specific edge as cost and sums over the traveled edges. Those travel times can either be given as input or (if not) are calculated by dividing length by maximum allowed speed (for the given vehicle type of a vehicle). You are right that the default case will lead to congestion and that is the reason why duaIterate exists. This will iteratively run the simulation and generate outputs with the simulated travel times and will feed them back to the duarouter which finds possibly new fastest routes. This mechanism however makes only sense for bigger networks. For a single intersection it is probably easiest to craft the routes by hand.
For the duaIterate errors please ask a separate question or open an issue directly at https://github.com/eclipse/sumo/issues.