1. there are different levels of lookahead distance: - the maximum considered distance es defined in https://github.com/eclipse/sumo/blob/de92290f118f38780aaf9b809a415ef981779b50/src/microsim/MSVehicle.cpp#L5787-L5848 - a dynamic distance that is being considered in the laneChangeModel which is computed based on the past and present speed of the vehicle as well as congestion. lcStrategic is applied to this second value. This distance (laDist) estimates how much space is needed for a lane change.
There are a number of special cases (if the ego vehicle needs to stop in the near future or if another vehice is stopped on the current lane), so to calculate either value you need to replicate the sumo code. There is no shortcut. 2. see above. The values lcAssertive and lcSpeedGain have no impact on the lookahead 3. No. You can active the debug macro DEBUG_WANTS_CHANGE to get this as command line output for selected vehicles. You could also adapt the code in MSLCM_LC2013::getParameter to make additional values of the internal state accessible via TraCI: https://github.com/eclipse/sumo/blob/a39499a3569d6239b3beec1a945c7d6042a29c9f/src/microsim/lcmodels/MSLCM_LC2013.cpp#L2099-L2115 Am Mo., 5. Juni 2023 um 21:04 Uhr schrieb Soumya Sharma via sumo-user < sumo-user@eclipse.org>: > Sorry for the multiple emails. > > If all these parameters are factors: > 1. How can I calculate the look-ahead distance of a vehicle type? > 2. how can I calculate the updated lookahead distance, when I change > parameters like lcStrategic, lcLookaheadLeft, lcAssertive, and lcSpeedGain? > 3. Is there a parameter that I can output to get the look-ahead distance > of vehicles in simulation, so I can track what changes occur as a result of > changing values of parameters mentioned in 2? > > Thank you. > > On Mon, Jun 5, 2023 at 2:36 PM Soumya Sharma <sshar...@ncsu.edu> wrote: > >> Thank you. >> Could you provide a little context of what this code, specifically those >> lines are doing? >> >> If I change lcStrategic from 1000 to 500, or 1500- what are some effects >> that I can expect? >> I have attached a set of files that I am using for your reference, I only >> change lcStrategic values in it and compare the results. >> >> >> On Mon, Jun 5, 2023 at 10:54 AM Jakob Erdmann <namdre.s...@gmail.com> >> wrote: >> >>> see >>> https://github.com/eclipse/sumo/blob/de92290f118f38780aaf9b809a415ef981779b50/src/microsim/MSVehicle.cpp#L5787-L5848 >>> >>> Am Mo., 5. Juni 2023 um 16:24 Uhr schrieb Soumya Sharma via sumo-user < >>> sumo-user@eclipse.org>: >>> >>>> Hi Jakob, >>>> Thanks for the information, that is very helpful. >>>> >>>> Also, in one of your previous emails, you mentioned: >>>> "The default look-ahead distance for strategic decision has a maximum >>>> range of about 3000m. You can reduce this distance by setting vType >>>> attribute 'lcStrategic' to a value in [0, 1[. " >>>> >>>> Where does this 3000m distance come from? is it the same as laDist? and >>>> where can I find these default values and the code corresponding to >>>> defaults? >>>> My goal is to understand how the look-ahead distance of a vehicle >>>> changes with changing parameters like "lcStrategic" and "lcLookaheadLeft", >>>> "lcAssertive" and "lcSpeedGain". >>>> >>>> Thanks! >>>> >>>> On Mon, Jun 5, 2023 at 7:57 AM Jakob Erdmann <namdre.s...@gmail.com> >>>> wrote: >>>> >>>>> - All these attributes are factors and thus unitless >>>>> - in the laDist computation, the value of LOOK_FORWARD is the time >>>>> (10s) which is then scaled >>>>> >>>>> >>>>> Am So., 4. Juni 2023 um 04:24 Uhr schrieb Soumya Sharma via sumo-user < >>>>> sumo-user@eclipse.org>: >>>>> >>>>>> Hello, >>>>>> I am trying to conduct a sensitivity analysis of car-following and >>>>>> lane-changing parameters in SUMO for hypothetical freeway segments (basic >>>>>> and weaving). I tried changing headway values (car-following) and >>>>>> lcStrategic values (lane-changing) for a basic segment. I used >>>>>> lcStrategic >>>>>> values of 500, 1000, and 1500 for trucks in simulations (length = >>>>>> 15.25m). >>>>>> My trucks are using the CACC model. >>>>>> The two metrics I am interested in are the travel rates (secs/ mi) by >>>>>> vehicle type and the number of lane changes per vehicle type. I found >>>>>> that >>>>>> there was no change in travel rate and a number of lane changes when I >>>>>> changed the value of lcStrategic to 500, 1000, and 1500. I don't >>>>>> understand >>>>>> why there was no effect of changing the parameter values. >>>>>> Next, I want to look into other parameters like "lcLookaheadLeft", >>>>>> "lcAssertive" and "lcSpeedGain". >>>>>> >>>>>> *Question*: I would like to understand the units of the parameters >>>>>> "lcStrategic" and "lcLookaheadLeft", "lcAssertive" and "lcSpeedGain". >>>>>> >>>>>> The SUMO documentation says: >>>>>> >>>>>> 1. lcStrategic: The eagerness for performing strategic lane >>>>>> changing. Higher values result in earlier lane-changing. default: 1.0, >>>>>> range [0-inf), -1 A value of 0 sets the lookahead-distance to 0 >>>>>> (vehicles can still change at the end of their lane) whereas -1 >>>>>> disables >>>>>> strategic changing completely. >>>>>> 2. lcLookaheadLeft: Factor for configuring the strategic lookahead >>>>>> distance when a change to the left is necessary (relative to right >>>>>> lookahead). default: 2.0, range [0-inf) >>>>>> 3. lcAssertive: Willingness to accept lower front and rear gaps >>>>>> on the target lane. The required gap is divided by this value. >>>>>> default: 1, >>>>>> range: positive reals >>>>>> 4. lcSpeedGain: The eagerness for performing lane changing to >>>>>> gain speed. Higher values result in more lane-changing. default: 1.0, >>>>>> range >>>>>> [0-inf) >>>>>> >>>>>> These definitions don't mention any units explicitly, are they all >>>>>> factors? i.e. unitless or are some of them in meters and some unitless? >>>>>> >>>>>> I was checking the code >>>>>> <https://github.com/eclipse/sumo/blob/main/src/microsim/lcmodels/MSLCM_LC2013.cpp#L1850>for >>>>>> LC2013 and found that look ahead distance (laDist) is being >>>>>> calculated as follows: >>>>>> >>>>>> laDist = myLookAheadSpeed * LOOK_FORWARD * myStrategicParam * (right >>>>>> ? 1 : myLookaheadLeft); >>>>>> >>>>>> >>>>>> If this is how the look-ahead distance for a vehicle is calculated >>>>>> when making lane-changing decisions, then both lcLookaheadLeft and >>>>>> lcStrategic specified will be used to calculate laDist but I don't know >>>>>> what what the units of any of these parameters are. For laDist to be in >>>>>> distance units, speed would be multiplied by time here. >>>>>> >>>>>> Please share any information that is available as it would help me >>>>>> understand my results better. >>>>>> >>>>>> Thanks, >>>>>> Soumya. >>>>>> _______________________________________________ >>>>>> 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 >>>>> >>>> >>>> >>>> -- >>>> Thank you, >>>> Soumya Sharma >>>> >>>> _______________________________________________ >>>> 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 >>> >> >> >> -- >> Thank you, >> Soumya Sharma >> >> > > -- > Thank you, > Soumya Sharma > > _______________________________________________ > sumo-user mailing list > sumo-user@eclipse.org > To unsubscribe from this list, visit > https://www.eclipse.org/mailman/listinfo/sumo-user >
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