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
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