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Re: [sumo-user] lcAssertive Behavior
Hello,
1) It really is a simple division. The formula is here:
https://github.com/eclipse/sumo/blob/1c5cd080e83c7cad30f96a6c6b70bb4d80478bdb/src/microsim/MSLaneChanger.cpp#L781
https://github.com/eclipse/sumo/blob/1c5cd080e83c7cad30f96a6c6b70bb4d80478bdb/src/microsim/MSLaneChanger.cpp#L812
https://github.com/eclipse/sumo/blob/1c5cd080e83c7cad30f96a6c6b70bb4d80478bdb/src/microsim/lcmodels/MSLCM_LC2013.cpp#L2102-L2104

2) Yes. It contributes to the getSecureGap function of the carFollowModel.

3). With these parameters, lane changed most likely did not fail due to lack of gap. You can check the lane-change status in sumo-gui to learn more about the vehicle state (lcState right, lcState left in the vehicle parameter dialog). If you cannot figure it out, send me a sample scenario.

4). This is to be expected as you are dividing the secureGap by 200 which pretty much makes it vanish. The correct formula would be this however:
requiredGap = secureBackGap + followerMinGap + subjectLength + subjectMinGap + secureFrontGap
(When computing the remaining gap between vehicles the minGap is already subtracted. In a sense it acts like a fixed extension of the vehicle length.)

regards,
Jakob





Am Sa., 11. Apr. 2020 um 00:32 Uhr schrieb Bae, Jong In <jbae42@xxxxxxxxxx>:
Hi,

My team is exploring on how 'lcAssertive' influences the gap accepted by the vehicle attempting to merge.
The test scenario is a 2-lane road where two vehicles are traveling (at 15m/s) on the right lane and the merging vehicle is traveling (at a higher speed) on the left lane.
Our experiments aim to find the minimum gap accepted at each lcAssertive value.

My questions are as follows:

  1. The SUMO vehicle definitions state that "the required gap is divided by the value of lcAssertive". However based on our experiment results, it seemed like the accepted gap is adjusted by some sort of a function of lcAssertive instead of a simple division. How does lcAssertive influence the accepted gap (required gap)? Is the function (or equation) available somewhere in the source code?
  2. Does the tau value play any role in the minimum accepted gap?
  3. We observed lane change failure with the default value of lcAssertive (lcAssertive="1") or lcAssertive = 2 even when the available gap was very large. All the other values were kept as default as well (minGap = 2.5, Tau = 1). The gap between the two vehicles in the target lane was 300m. Is this a reasonable result?
  4. Our results show that with MinGap = 0 and lcAssertive as high as 200~300, the minimum accepted gap was reduced to 0.1m + vehicle length. If the required gap is determined by secureBackGap + subjectLength + subjectMinGap + secureFrontGap, does SUMO let us ignore the secureBackGap and secureFrontGap when MinGap is set as 0?
Thank you,

-James Bae 
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