Yes. That should work  (see also
https://sumo.dlr.de/docs/Tutorials/FundamentalDiagram.html).

Am Mo., 22. Nov. 2021 um 23:02 Uhr schrieb François Vaudrin <
[email protected]>:

> Hello Jakob,
>
>
> Thanks for the reference, that sounds very interesting to me.
>
>
> Since there is no closed loop on a highway, I'm thinking of artificially
> creating density with variable speed panels toward the end of the network.
>
> Does it make sense?
>
> Best
>
> *François *
>
> *De :* sumo-user <[email protected]>
> <[email protected]> de la part de Jakob Erdmann
> <[email protected]> <[email protected]>
> *Envoyé :*ect User discussions <[email protected]>
> <[email protected]>
> *Objet :* Re: [sumo-user] Publics Roads (BPR) formula
>
> Hello François,
> Most likely, your scenario does not reach the required traffic density.
> Check for insertion-backlog in you scenario (
> https://sumo.dlr.de/docs/Simulation/VehicleInsertion.html#investigating_insertion_delay
> <https://can01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsumo.dlr.de%2Fdocs%2FSimulation%2FVehicleInsertion.html%23investigating_insertion_delay&data=04%7C01%7Cfrancois.vaudrin.1%40ulaval.ca%7Cb64fbaf2a869463e485a08d9ab69f48e%7C56778bd56a3f4bd3a26593163e4d5bfe%7C1%7C0%7C637729294883782117%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=98BEjcmXiMLu8SMOAidVZz3%2BvX8j6aTNlr4%2B%2BLTA0GU%3D&reserved=0>
> )
> Feel free to post your files to enable more specific advice.
>
> regards,
> Jakob
>
> Am Fr., 19. Nov. 2021 um 07:24 Uhr schrieb François Vaudrin <
> [email protected]>:
>
> This is  the BPR formula.
>
> Best regards
>
>
> *François *
>
> ------------------------------
> *De :* François Vaudrin <[email protected]>
> *Envoyé :* vendredi 19 novembre 2021 01:07
> *À :* mvaudrin <[email protected]>
> *Objet :* TR: [sumo-user] Publics Roads (BPR) formula
>
> Info.
>
>
> *François *
> ------------------------------
> *De :* François Vaudrin <[email protected]>
> *Envoyé :* vendredi 19 novembre 2021 01:06
> *À :* Sumo project User discussions <[email protected]>
> *Objet :* RE: [sumo-user] Publics Roads (BPR) formula
>
>
> Thank you for your answer Qichao,
>
>
> You're right about the BPR formula, but that's not what we see with the
> SUMO simulations.
>
>
> The function we get is a line of the following form:
>
>
> y = mx + b
>
>
> Whereas the function of BPR is exponential and tends towards an asymptote.
>
>
> T = Tff (1 + α (Q*Qpc)**β
>
>
>
> Perhaps this theory is debatable, because it dates from 1964 and the
> microsimulation tools were not available at the time.
>
>
> But maybe I am wrong or there is something that I do not understand.
>
>
> Best
>
>
> *François *
> ------------------------------
> *De :* sumo-user <[email protected]> de la part de Qichao
> Wang <[email protected]>
> *Envoyé :* jeudi 18 novembre 2021 22:35
> *À :* Sumo project User discussions <[email protected]>
> *Objet :* Re: [sumo-user] Publics Roads (BPR) formula
>
> At much lower flow rates, you should see a flat line. As you increase the
> volume, you will see a point when the rate increases. When the capacity is
> lower than the demand, as time goes, the travel time should keep
> increasing. That basically means that there is no stable observed travel
> time (i.e., not a single point on your graph).
>
> You don’t need to create bottlenecks to fit a highway performance
> function. You can create a loop network to see the impact on having more
> cars on road.
>
> Thanks,
> Qichao
>
> On Thu, Nov 18, 2021 at 8:07 PM François Vaudrin <
> [email protected]> wrote:
>
> Hello everyone,
>
>
> Has anyone ever tested the Bureau of Public Roads (BPR) formula with SUMO?
>
>
> This formula was developed in the 1960s by the BPR to estimate travel time
> as a function of road capacity under free-flow conditions (such as on a
> highway). The transport time increases exponentially depending on the
> capacity of the road (see diagram in the attached file).
>
>
> We would like to reproduce these phenomena with SUMO by gradually
> increasing the traffic flow and measuring the total time to empty the
> network. We then reproduced the results on a graph to check if it is
> similar to that of the BPR.
>
>
> The problem is that we are not getting an exponential function, but a
> straight line (see results in the attached file) and that is not what the
> BPR predicted in the 1960s.
>
>
> Does that make sense?
>
>
> Do we have to introduce a bottleneck (or reduce the speed) at the end of
> the network to create a queue or traffic jam?
>
>
> Thank you
>
>
> *François *
> CANADA
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