| [sumo-user] Calibration of mesoscopic simulation |
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Dear SUMO developer team, I am trying to calibrate a mesoscopic simulation for an urban arterial and get results as close as possible to the microscopic version of the same scenario. I get very good results when I use high values for taus (tau_ff=tau_fj=2,
tau_jf=3.9 and tau_jj=3) and small meso-edgelength=10m. These values seems to be very extreme in comparison to the defaults ones and the suggested range, which makes me wonder if I have understood the meaning of each parameter correctly.
In the dissertation of Nils Eissfeldt tau is defined as service rate 1/q which can be obtained from the fundamental diagram. I think it is a bit different from its implementation in SUMO as it is discussed in
https://github.com/eclipse/sumo/issues/5709 these values are net-time gaps between vehicles while leaving segments. This brings me to the question
how the points on the fundamental diagram i.e. jam density, critical density, maximum flow, backward wave speed and free-flow speed can be calculated using the tau values?
If I understood it correctly, it seems that the parameter minGap of the car-following model affects the meso simulation as well which then sets the value of jam density = 1000/(vehicle_length+minGap). How is this then
interlinked with tau_jj? The other point is that in the dissertation on page 70 formula 3.24 there is a relationship between tau_jf and tau_jj defined indicating that tau_jj is bigger than tau_jf but in SUMO it is the other way around.
Thank you for you r support, Sasan
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