Hello,
you are posing an interesting question that hasn't really come up before.
It appears that typical scenario creators didn't have access to both
OD-Matrix and counting data. Hence, there is a gap in documentation and
tooling for this use case.
Your thoughts on the matter are correct.

With regard to 1. (using equilibrium routes rather than free-flow routes)
you could employ the following alternatives:
- create candidate routes by loading the trips in sumo and writing
--vehroute-output (see
https://sumo.dlr.de/docs/Demand/Dynamic_User_Assignment.html#oneshot-assignment
)
- create move variance in the routes by running duarouter with option
--weights.random-factor

With regard to 2, you should be able to use the routeSampler.py option
--od-files to ensure that all vehicles are put into the simulation (rather
than only those that pass city-center counting locations). This should in
principle allow a perfect fit with the OD-Matrix.

There are some limitations to this approach:
- there is currently no tooling to generated the od-files (i.e.
https://github.com/eclipse/sumo/issues/10058)
- by using a fixed assignment of trips to edges (from od2trips), you are
losing degrees of freedom that might be needed to match the counting data.
A possible fix is outlined at https://github.com/eclipse/sumo/issues/6890
- there is no guarantee that the sampled routes have a similar frequency
compared to the "equilibrium" input. You can set option --weighted to
improve this likelihood but if the counts go in a particular way you could
get artifacts

Overall I'd be quite interested in hearing about your progress if you chose
to follow the OD2trips + routeSampler approach.
If you happen to work on tooling, pull requests are also welcome.

regards,
Jakob





Am Do., 27. Jan. 2022 um 09:45 Uhr schrieb Schaniel Joel <
joe...@student.ethz.ch>:

> Dear all,
>
>
> I am working with a real-life network in SUMO and could need your advice
> for calibrating the simulation.
> I have an OD-matrix and a network given. Further, I have traffic count
> data from edge counts in the city center (but not from the rest of the
> region).
>
> So far, I have created TAZ's according to my OD matrix and generated trips
> with od2trips. This comes with the benefit that origins and destinations
> are spread over the whole TAZ.
>
> Now, I would like to use routeSampler.py to calibrate the traffic
> according to the edge count data. My idea so far was to:
>
>    1. Use duarouter to convert trips to routes (since origins and
>    destinations spread over all edges this would basically create a route for
>    each trip)
>    2. Use this set of routes and my edge counts as input for
>    routeSampler.py
>
>
> However, I see two major problems with this approach.
>
>    - Duarouter creates all routes based on free-flow speed and does not
>    include alternative routes which would only be used during congestion.
>    - All traffic count data is from the city center, therefore,
>    routeSampler would not use any route that does not pass an edge with
>    traffic counts (e.g. traffic that bypasses the city center).
>
>
> The first problem could probably be solved by using duaIterate.py,
> creating a set of routes in the dynamic user equilibrium.
> But the second point seems to be tricky. In the documentary
> <https://sumo.dlr.de/docs/Tools/Turns.html#origin-destination_restrictions>,
> it is also briefly mentioned that OD files can be used, but only
> edge-based. Could I work with this option to make sure the routes still fit
> the OD more or less?
>
>
> Are my thoughts correct? Would it be better to use another tool to try for
> example to scale the OD as a whole to fit the traffic counts?
>
>
> Thanks a lot for your help in advance!
>
>
> Best regards,
>
> Joel
> _______________________________________________
> sumo-user mailing list
> sumo-user@eclipse.org
> To unsubscribe from this list, visit
> https://www.eclipse.org/mailman/listinfo/sumo-user
>
_______________________________________________
sumo-user mailing list
sumo-user@eclipse.org
To unsubscribe from this list, visit 
https://www.eclipse.org/mailman/listinfo/sumo-user

Reply via email to