How to use traci and sumo in python?

Question

I am trying to simulate an intersection with traffic light and detectors and train a machine learning classifier to use the information from the detectors to set the traffic light phase.

I am able to run the simulation using:

import traci
traci.start(sumoCmd) 
step = 0
while step < 1000:
    traci.simulationStep()
    step += 1
traci.close()

However, I do not know how to get information about cars. I have e2 detectors, but I don't know how to use their output. I don't understand traci and sumo documentation.

I tried this code:

import traci
traci.start(sumoCmd) 
step = 0
lanearea = traci._lanearea.LaneAreaDomain()
detlist = lanearea.getIDList()
while step < 1000:
    traci.simulationStep()
    print([lanearea.getLastStepVehicleNumber(det) for det in detlist])
    step += 1
traci.close()

but it does not work. I am getting this error

detlist = lanearea.getIDList()
return self._getUniversal(tc.ID_LIST, "")
result = self._connection._sendReadOneStringCmd(self._cmdGetID, varID, objectID)
AttributeError: 'NoneType' object has no attribute '_sendReadOneStringCmd'

Can anyone tell me how to fix this code? Or more generally, if anyone knows it, how to use any function in: http://sumo.dlr.de/wiki/TraCI/Lane_Area_Detector_Value_Retrieval or any other ways to get information about cars.

Welcome to StackOverflow. Please read and follow the posting guidelines in the help documentation, as suggested when you created this account. [On topic](http://stackoverflow.com/help/on-topic), [how to ask](http://stackoverflow.com/help/how-to-ask), and [... the perfect question](https://codeblog.jonskeet.uk/2010/08/29/writing-the-perfect-question/) apply here. StackOverflow is not a design, coding, research, or tutorial resource. — Prune, Nov 01 '18 at 19:29
In particular, you seem to ask us to make up for the lack of sumo/traci documentation and examples. This seems *very* broad and quite off-topic for Stack Overflow. If you have a particular example that needs help, please post a [Minimal, complete, verifiable example](http://stackoverflow.com/help/mcve), and someone will probably try to help. — Prune, Nov 01 '18 at 19:31
I would prefer to have a more general answer, but if you want to give me an answer to only one coding bug, there is this one that I mention in my question: import traci traci.start(sumoCmd) step = 0 lanearea = traci._lanearea.LaneAreaDomain() detlist = lanearea.getIDList() while step < 1000: traci.simulationStep() print([lanearea.getLastStepVehicleNumber(det) for det in detlist]) step += 1 traci.close() — Nicolas, Nov 01 '18 at 20:33
I am getting this error detlist = lanearea.getIDList() return self._getUniversal(tc.ID_LIST, "") result = self._connection._sendReadOneStringCmd(self._cmdGetID, varID, objectID) AttributeError: 'NoneType' object has no attribute '_sendReadOneStringCmd' — Nicolas, Nov 01 '18 at 20:35
Please edit such things into you question. As you can see, code and output do *not* format well in comments. Make sure that your code example is complete. — Prune, Nov 01 '18 at 20:36

score 2 · Accepted Answer · answered Nov 02 '18 at 14:53

There is no need to instantiate the lanearea yourself. Just use traci.lanearea.getIDList() and traci.lanearea.getLastStepVehicleNumber(det) so your program should look like:

import traci
traci.start(sumoCmd) 
step = 0
detlist = traci.lanearea.getIDList()
while step < 1000:
    traci.simulationStep()
    print([traci.lanearea.getLastStepVehicleNumber(det) for det in detlist])
    step += 1

Also the close is not necessary.

score 0 · Answer 2 · answered May 25 '20 at 20:31

You could also use the following way to get vehicle ID list

vehicle_id_list = traci.vehicle.getIDList()

And then IDs obtained can be used to get various parameters like

waiting time: traci.vehicle.getAccumulatedWaitingTime(vehicle_id)
road id: traci.vehicle.getRoadID(vehicle_id) and so on.

How to use traci and sumo in python?

2 Answers2