Re: [sumo-user] Questions about Gap between two vehicles and getLeader m

[Jakob Erdmann via sumo-user <sumo-user@xxxxxxxxxxxxxxxxxxxxx>]

Hello,
as was pointed out, the physical distance between vehicles is equal to the
result of getLeader + minGap. Therefore a getLeader value of 0.001 likely
belongs to a vehicle that is standing behind the leader vehicle in a jam or
waiting at an intersection with the minGap spacing.
Hence, the values are not strange at all.
regards,
Jakob

2017-07-27 9:49 GMT+02:00 Alessandro Virgilio via sumo-user <
sumo-user@xxxxxxxxxxxxxxxxxxxxx>:

> Hi Michael,
>
> in my previous tests I used the default car following model
> (carFollowing-Krauss)specifing the mingGap as  minGap = "1" and in some
> circumstances I got this values from the getLeader method.
>
>
> 39.04120129
>
>
> 30.80244446
>
>
> 22.25698386
>
>
> 12.35251871
>
>
> 5.246203698
>
>
> 1.330938864
>
>
> 0.028784268
>
>
> 0.008626148
>
>
> 0.001707736
>
>
> 0.001297148
>
>
> 0.001090875
>
>
> 0.001022937
>
>
> 0.001010266
>
>
> 0.001003249
>
>
> 0.001000934
>
>
> 0.00100031
>
>
> 0.001000016
>
>
> 0.001000008
>
>
> 0.001000001
>
>
> 0.001
>
>
> 0.001
>
>
> 0.001
>
>
> 0.001
>
>
> 0.001
>
>
> After the last value, the leader disappeared and i didn't get any result
> from getLeader method, as it is defined.
>
> Besides, I noticed that the streak of these "strange" values is often
> short, less than 15/20 steps.
>
> I tried the original Krauss car following model (attribute=KraussOrig1)
> but I obtained worse results. In particular the distance is quite always
> under the specified gap.
>
> Should I try some different car following models?
>
>
> Thank you.
>
>
> Regards,
>
> Alessandro
>
> ________________________________
> Da: Michael Behrisch <oss@xxxxxxxxxxx>
> Inviato: mercoledì 26 luglio 2017 17:23:09
> A: Alessandro Virgilio; sumo-user@xxxxxxxxxxxxxxxxxxxxx
> Oggetto: Re: [sumo-user] Questions about Gap between two vehicles and
> getLeader method
>
> Hi Alessandro,
> if you use the default Krauss model the vehicles should always respect
> the minGap except for rare circumstances which trigger emergency
> breaking (missing or short yellow phases in traffic lights for
> instance). Can you send a small example?
>
> Best regards,
> Michael
>
> Am 26.07.2017 um 11:00 schrieb Alessandro Virgilio via sumo-user:
> > Hi, I have a question about the minGap attribute and the output given by
> the method getLeader in Traci for python.
> >
> >
> > I defined two vehicle types, giving some attributes and the mingap.
> Then, for each simulated vehicle, I extracted the distance with the leading
> vehicle, using the method getLeader.
> >
> >
> > Sometimes it happens that the distance with the leading vehicle is less
> than the specified minGap. I can't understand if it's a bug or I
> misunderstood the meaning of the minGap attribute. Is it applied only with
> vehicles stuck in traffic jam? In this case, is there any way to define a
> minum distance to keep for each vehicle during the simulation?
> >
> >
> > Using sumo 0.30.0 and python 2.7
> >
> > Thank You.
> >
> >
> > Regards,
> > Alessandro V
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