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Re: [sumo-user] krauss model
There is no literature beyond the model source code at the moment.
The code is found here:
https://github.com/eclipse/sumo/blob/master/src/microsim/cfmodels/MSCFModel_Krauss.cpp
https://github.com/eclipse/sumo/blob/master/src/microsim/cfmodels/MSCFModel.h
https://github.com/eclipse/sumo/blob/master/src/microsim/cfmodels/MSCFModel_Krauss.cpp

Some pointers for understanding the code:
- the Sumo implementation is in the spirit of the original Krauss model: use the fastest speed that still allows safe braking with the desired maximum deceleration.
- The minGap value is subtracted from gap before behind given to the car-following model (the model computes speed for keeping the resulting gap at 0 in case the leader brakes). This ensures that the minGap is always maintained. Consequently, minGap violations are already flagged like collisions for the Krauss model by default.
- The fastest safe speed is affected by discretization effects from the simulation step-length (this complicates the formulas)
- The fastest safe speed is affected by the speed-space integration (Euler / Ballistic). For this reason you have two code paths in each of the model functions.
- The original Krauss model assumed that all vehicles had the same maximum deceleration. The original Krauss safety equation is actually invalid if the follower can break faster than the leader so additional code is added in https://github.com/eclipse/sumo/blob/f831daab305c0f3fd62e59fdf2c9af04947c6464/src/microsim/cfmodels/MSCFModel.h#L328-L335. For a technical discussion of this effect, see https://arxiv.org/abs/1902.04927

regards,
Jakob

Am Mo., 16. März 2020 um 23:03 Uhr schrieb Graziano Manduzio <graziano.manduzio@xxxxxxxxx>:
Hi everyone,

I solved a problem related to departed delay by reducing a parameter of the model krauss: the Tau that I think is the human reaction time.
This documentation explain which are the krauss model parameters:


but the problem is that I don't understand the exactly way by means the Krauss model is implemented. I don't found much in literature about that and for example looking at this article


  and the way how is calculated the distance between two consecuitive vehicle, they don't match the calculations in my scenario.
So ,if is possible, I'd like to undesrtand exactly the way the distance between two vehicle is calculated in sumo and the way how it depens on the parameters explained in the first documentation I attacked.

Thanks in advance,
Graziano 

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