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 <[email protected]> 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 <[email protected]> > 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 < >> [email protected]>: >> >>> 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 <[email protected]> >>> 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 < >>>> [email protected]>: >>>> >>>>> 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 >>>>> [email protected] >>>>> To unsubscribe from this list, visit >>>>> https://www.eclipse.org/mailman/listinfo/sumo-user >>>>> >>>> _______________________________________________ >>>> sumo-user mailing list >>>> [email protected] >>>> To unsubscribe from this list, visit >>>> https://www.eclipse.org/mailman/listinfo/sumo-user >>>> >>> >>> >>> -- >>> Thank you, >>> Soumya Sharma >>> >>> _______________________________________________ >>> sumo-user mailing list >>> [email protected] >>> To unsubscribe from this list, visit >>> https://www.eclipse.org/mailman/listinfo/sumo-user >>> >> _______________________________________________ >> sumo-user mailing list >> [email protected] >> To unsubscribe from this list, visit >> https://www.eclipse.org/mailman/listinfo/sumo-user >> > > > -- > Thank you, > Soumya Sharma > > -- Thank you, Soumya Sharma
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