1) yes 2) in your scenario with max departSpeed and lcAssertive=2, check whether the merging vehicles a) fail to merge because they do not accept the gaps -> increase lcAssertive b) have plenty of space for merging (because main flow vehicles can still move to another lane or the traffic generally is not very dense) -> increase traffic density further (see https://sumo.dlr.de/docs/Simulation/VehicleInsertion.html#global_options_that_affect_departure )
Am Fr., 3. Juli 2020 um 16:25 Uhr schrieb Solmaz Razmi Rad - CITG < [email protected]>: > Dear Jakob, > > > > I did what you suggested: > > > > · *Increase traffic:* I had tested higher flow and did not see any > changes. That was because of delayed insertion. I forced insertion by > increasing the departSpeed and now I see a significant difference in > timeGap values. > > · *Reduce cooperation changing:* I tested lcCooperative equal to > zero but this was not the best option since lots of vehicles come to a > standstill situation (speed=0) just before the end of the ramp which is not > desired in my simulation scenario. > > · *Set lcAssertive to lower values (i.e 0.5 or lower): *According > to the definitions, requiredGap is divided by lcAssertive. So, if > lcAssertive is lower than 1, the Gap will be larger. The combination 0f max > departSpeed and lcAssertive=2 led to the smallest timeGaps. However, > compared to the field results (van Beinum et al, 2018), with the same flow, > timeGaps are still quite large. Now I have two more questions: > > 1. In lane change output file*, I assume the gaps (leader and > follower) do not include the subject length.* I add 5m as the vehicle > length in calculating the gap. Is that right? > > 2. Is there any other way to make the vehicles accept smaller gaps > in lane changing? I even set tau=0.5, but the merging vehicles (from the > ramp) just stop at the end of the ramp and do not accept small gaps until > the main flow vehicles stop for them. They are just so conservative in lane > changing. > > > > Bests, > > Solmaz > > > > *Reference*: van Beinum, A., Farah, H., Wegman, F., Hoogendoorn, S., > 2018. Driving behaviour at motorway ramps and weaving segments based on > empirical trajectory data. Transp. Res. Part C Emerg. Technol. 92, 426–441. > https://doi.org/10.1016/j.trc.2018.05.018 > > > > *From:* [email protected] <[email protected]> *On > Behalf Of *Jakob Erdmann > *Sent:* donderdag 2 juli 2020 09:42 > *To:* Sumo project User discussions <[email protected]> > *Subject:* Re: [sumo-user] Gap acceptance in lane changing > > > > In your scenario most of the changing happens from the on-ramp and is > aided by cooperative lane-changing of the main flow (main-flow vehicles > move away from the right lane to let ramp vehicles merge). > > You will see an effect of lcAssertive (and also from tau) if you either > > - increase traffic > > - reduce cooperative changing > > - set lcAssertive to lower values (i.e 0.5 or lower) > > > > > > Am Mi., 1. Juli 2020 um 17:15 Uhr schrieb Solmaz Razmi Rad - CITG < > [email protected]>: > > Dear Jakob, > > > > Attached you can find the simplified project. I had to keep the number of > vehicles quite high so that every vehicle has a leader and follower gap. > Otherwise, there would be no gap to compare. > > As you see in the *my_lane_change_file.xml* for lcAssertive 3 and 30, > leader and follower gaps have changed marginally but not significantly. > > Running the simulation with lcAssertive=3 resulted in TimeGap ( μ= 6.27, > std=3.26) whereas lcAssertive=30 resulted in TimeGap ( μ= 6.07, std= 3.35). > Calculations are available in Python files LC3 and LC30. > > Regarding Tau, I tested Tau=20 vs Tau=1.6 and saw no change in TimeGap > values. > > > > Bests, > > Solmaz > > > > > > *From:* [email protected] <[email protected]> *On > Behalf Of *Jakob Erdmann > *Sent:* woensdag 1 juli 2020 15:51 > *To:* Sumo project User discussions <[email protected]> > *Subject:* Re: [sumo-user] Gap acceptance in lane changing > > > > In my experiments there is a huge difference. Please try to find a minimal > version of your scenario that reproduces your problem and then send it to > the list or attach it to a github-issue. > > > > Am Di., 30. Juni 2020 um 17:20 Uhr schrieb Solmaz Razmi Rad - CITG < > [email protected]>: > > Yes, I used the actual gap values (leaderGap, followerGap). Just made a > mistake to mention secureGap earlier. But still, I don’t see any > differences in the actual gap values (leaderGap, followerGap) with changing > lcAssertive. > > > > *From:* [email protected] <[email protected]> *On > Behalf Of *Jakob Erdmann > *Sent:* dinsdag 30 juni 2020 17:12 > *To:* Sumo project User discussions <[email protected]> > *Subject:* Re: [sumo-user] Gap acceptance in lane changing > > > > The secureGaps are not only influenced by tau but also by vehicle speed. > Changing tau can have a major influence on scenario dynamics including > average speeds so a naive interpretation of the distribution is misleading. > > > > the *secureGap values in the lanechange-output are always those for > lcAssertive 1 (because when the gaps are reduced due to lcAssertive this is > not really secure anymore). What you would rather look at are the actual > gap values (leaderGap, followerGap) which are influenced by lcAssertive. > > As above, due to the influence of lcAssertive on scenario dynamics, the > distribution of gaps is hard to interpret. > > You could try to look at time-headways instead i.e. > leaderGap/(leaderSpeed-speed) or leaderGap/speed (also for the secureGaps). > > > > regards, > > Jakob > > > > > > Am Di., 30. Juni 2020 um 14:52 Uhr schrieb Solmaz Razmi Rad - CITG < > [email protected]>: > > Hi Jakob, > > > > Following our discussion below, I tried to run the simulation with > different *lcAssertive* and *tau* values to see how they affect the value > of requiredGap (in seconds) which is calculated as: “(secureBackGap + > followerMinGap + subjectLength + subjectMinGap + secureFrontGap)/Speed” and > derieved from the *lane_change_output* file. > > > > To my surprise: > > · Tau did not influence the requiredGap at all. I tested tau=1.6 s > (recommended for IDM) and tau=0.5 s. Both of them resulted in the same mean > and standard deviation for requiredGap. > > · As you confirmed earlier, the requiredGap is divided by the value > of lcAssertive. But the results did not support this one either. Running > the simulation with lcAssertive=3 resulted in requiredGap ( μ= 6.0509, > std=3.239) whereas lcAssertive=30 resulted in requiredGap ( μ= 6.107, std= > 3.22). It seemed like the accepted gap is adjusted by some sort of a > function of lcAssertive instead of a simple division and even Higher > lcAssertive value resulted in higher requiredGap! > > > > Am I doing some calculations wrong? > > > > Regards, > > Solmaz > > > > > > *From:* [email protected] <[email protected]> *On > Behalf Of *Jakob Erdmann > *Sent:* vrijdag 19 juni 2020 15:18 > *To:* Sumo project User discussions <[email protected]> > *Subject:* Re: [sumo-user] Gap acceptance in lane changing > > > > 1) Yes > > 2) you can set minGap=0 to lower the size of accepted gaps. At high speeds > you will not see adverse effects but gaps will probably appear too small at > lower speeds. Some car-following models such as IDM require minGap as an > additional buffer for collision-free driving. > > > > Am Fr., 19. Juni 2020 um 11:55 Uhr schrieb Solmaz Razmi Rad - CITG < > [email protected]>: > > 1. So, the requireGap, depends on the followSpeed. And followSpeed > should be also influenced by “tau”. *Then the requireGap is always a > function of tau. Is this right?* Can I say, if I have a distribution for > tau, I will have a variation for gap acceptance (requireGap)? > > 2. And regarding the minGap, can I assume minGap=0 if lane change > happens without any jam? > > > > > > *From:* [email protected] <[email protected]> *On > Behalf Of *Jakob Erdmann > *Sent:* vrijdag 19 juni 2020 11:39 > *To:* Sumo project User discussions <[email protected]> > *Subject:* Re: [sumo-user] Gap acceptance in lane changing > > > > 1) yes > > 2) these are computed by the car-follow model functions. They generally > are consistent with the followSpeed function so that neither the ego > vehicle nor its follower on the target lane have to perform any extra > braking after the lane change is completed. > > 3) if a jam develops immediately after lane changing, vehicles must still > be able to maintain the configured minGap, thus the value is already > considered during lane changing > > > > > > > > Am Fr., 19. Juni 2020 um 11:26 Uhr schrieb Solmaz Razmi Rad - CITG < > [email protected]>: > > Hi there, > > > > I am trying to investigate the impact of gap acceptance in lane changing > around on-ramps on the capacity of a freeway. I want to use a distribution > for the gaps accepted while lane changing. I realized that the parameter > which controls the gap acceptance is “lcAssertive” (But if I understood > correctly, lcAssertive can influence the size of accepted gap but it > doesn’t define the gap itself) . The SUMO vehicle definitions state that > "the required gap is divided by the value of lcAssertive". When searching > for the definition of requiredGap, I came across this page ( > http://sumo-user-mailing-list.90755.n8.nabble.com/sumo-user-lcAssertive-Behavior-td3244.html > <https://urldefense.proofpoint.com/v2/url?u=http-3A__sumo-2Duser-2Dmailing-2Dlist.90755.n8.nabble.com_sumo-2Duser-2DlcAssertive-2DBehavior-2Dtd3244.html&d=DwMFaQ&c=XYzUhXBD2cD-CornpT4QE19xOJBbRy-TBPLK0X9U2o8&r=VL7LZgp9uGc2UAWfyMuvx0_-p-5L033DSD_Kyqc84V0&m=Azr-wRMy-oqbdQPxVMa10suRW_8GP2m1_exyRCASvLs&s=1_X9_XuHTSeys_pvvjFkk9IqsmM1Ut-3853wSBryXAE&e=> > ) where Jakob explained about requiredGap: “requiredGap = secureBackGap + > followerMinGap + subjectLength + subjectMinGap + secureFrontGap”. > > I have a couple of questions here: > > 1. What exactly is requiredGap? Is this the same as the accepted > gap in lane changing? > > 2. How are secureBackGap or secureFrontGap defined? Is there any > relation between tau and secureBackGap or secureFrontGap? > > 3. From what I have understood, MinGap is the jam distance or the > distance which vehicles keep when standstill. How does this contribute to > gap acceptance in lane changing? > > I appreciate your help in advance. > > > > Regards, > > Solmaz > > > > _______________________________________________ > sumo-user mailing list > [email protected] > To unsubscribe from this list, visit > https://www.eclipse.org/mailman/listinfo/sumo-user > <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.eclipse.org_mailman_listinfo_sumo-2Duser&d=DwMFaQ&c=XYzUhXBD2cD-CornpT4QE19xOJBbRy-TBPLK0X9U2o8&r=VL7LZgp9uGc2UAWfyMuvx0_-p-5L033DSD_Kyqc84V0&m=Azr-wRMy-oqbdQPxVMa10suRW_8GP2m1_exyRCASvLs&s=biv3B1xwRStkY_qfVxHwgFeamxhI4u9lW005-8eH1Zo&e=> > > _______________________________________________ > sumo-user mailing list > [email protected] > To unsubscribe from this list, visit > https://www.eclipse.org/mailman/listinfo/sumo-user > <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.eclipse.org_mailman_listinfo_sumo-2Duser&d=DwMFaQ&c=XYzUhXBD2cD-CornpT4QE19xOJBbRy-TBPLK0X9U2o8&r=VL7LZgp9uGc2UAWfyMuvx0_-p-5L033DSD_Kyqc84V0&m=iBDmvSS0IgQ9qOCrRrhbkzc3kSxARq-smSRkAHIlZIM&s=KEUa2GWs8E9RH3ZBaJDsyzAd747PwuWyFPB_imjVIv4&e=> > > _______________________________________________ > sumo-user mailing list > [email protected] > To unsubscribe from this list, visit > https://www.eclipse.org/mailman/listinfo/sumo-user > <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.eclipse.org_mailman_listinfo_sumo-2Duser&d=DwMFaQ&c=XYzUhXBD2cD-CornpT4QE19xOJBbRy-TBPLK0X9U2o8&r=VL7LZgp9uGc2UAWfyMuvx0_-p-5L033DSD_Kyqc84V0&m=CK3-thID0N6m-bDkTm_L5hY_J82JnbXVYTH1IXzu0hg&s=aW7wfCSLQPVBCJBP7DEJm-hm6hg4HHCRJ5Zlm09s4zQ&e=> > > _______________________________________________ > sumo-user mailing list > [email protected] > To unsubscribe from this list, visit > https://www.eclipse.org/mailman/listinfo/sumo-user > <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.eclipse.org_mailman_listinfo_sumo-2Duser&d=DwMFaQ&c=XYzUhXBD2cD-CornpT4QE19xOJBbRy-TBPLK0X9U2o8&r=VL7LZgp9uGc2UAWfyMuvx0_-p-5L033DSD_Kyqc84V0&m=1jIYX5goukkWN9jFbl2B2z9nF-TEs5HXWJKNHipUkNs&s=FRGrSjaOEUpHHnX7CqfVC1iTRWpCGqX8EGR3plMrH3E&e=> > > _______________________________________________ > sumo-user mailing list > [email protected] > To unsubscribe from this list, visit > https://www.eclipse.org/mailman/listinfo/sumo-user > <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.eclipse.org_mailman_listinfo_sumo-2Duser&d=DwMFaQ&c=XYzUhXBD2cD-CornpT4QE19xOJBbRy-TBPLK0X9U2o8&r=VL7LZgp9uGc2UAWfyMuvx0_-p-5L033DSD_Kyqc84V0&m=NQSZXtJx_6-TnCGCX2ZX_wfaut2yxnf5cFMVU2CRP78&s=qHYref_tKLtlT53eGZxdZ-AioGkKeEc3J4tvNiUxQ7Q&e=> > > _______________________________________________ > sumo-user mailing list > [email protected] > To unsubscribe from this list, visit > https://www.eclipse.org/mailman/listinfo/sumo-user >
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