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Re: [sumo-user] Calculation of HBEFA4 emission model

Dear Jakob,

 

thank you for the answers. Just one more thing – so both point 2 & 3 would be incorporated if I install the nightly version?

 

 

Warmest regards,

 

Addina

 

Von: sumo-user <sumo-user-bounces@xxxxxxxxxxx> Im Auftrag von Jakob Erdmann via sumo-user
Gesendet: Freitag, 21. März 2025 10:14
An: Sumo project User discussions <sumo-user@xxxxxxxxxxx>
Cc: Jakob Erdmann <namdre.sumo@xxxxxxxxx>
Betreff: Re: [sumo-user] Calculation of HBEFA4 emission model

 

1. The coefficients are obtained by computing a fit that optimizes over all the colored curves at once.

2. The code at https://github.com/eclipse-sumo/sumo/blob/7308a1b9569b4fc8edc99c891063b4366a31d0a8/src/utils/emissions/HelpersHBEFA4.h#L114 is from an older version where road slope was not take into account. This was changed only recently: https://github.com/eclipse-sumo/sumo/issues/16307

3. The angle in full output is the bearing of the vehicle. To get the slope you may download the nightly version starting tomorrow (https://github.com/eclipse-sumo/sumo/issues/16389)

 

regards,

Jakob

 

Am Fr., 21. März 2025 um 09:24 Uhr schrieb Addina Shafiyya Ediansjah via sumo-user <sumo-user@xxxxxxxxxxx>:

Dear all,

 

I am trying to understand the calculation of the HBEFA4 emission module and came across a few questions:

 

  1. According to a previous discussion (https://github.com/eclipse-sumo/sumo/issues/15206), SUMO takes emissions for a particular vehicle class and emission type from the database and fits it over a range of speed and acceleration. The different colored lines in the attached graphs correspond to seven discrete acceleration values. SUMO then takes f[0] to f[6] to calculate the emissions for a particular vehicle class. Are the coefficients f[0] to f[6] thus the average value of the seven different colored lines?
  2. HBEFA which is not dependant on acceleration is compensated by taking its dependency on road slope. As far as I understand, SUMO calculates the added acceleration it needs to exert to overcome the road slope. One documentation (https://sumo.dlr.de/doxygen/d2/db0/_helpers_h_b_e_f_a4_8h_source.html) (line 113) states the calculation of a2, which takes the vehicle acceleration and then adds it with (gravity * sin θ). I could not find this calculation step on another documentation page (https://github.com/eclipse-sumo/sumo/blob/7308a1b9569b4fc8edc99c891063b4366a31d0a8/src/utils/emissions/HelpersHBEFA4.h#L114). Is it already embedded in another function for the second documentation or is there another reason behind it?
  3. Not directly related to the HBEFA4 emission module – but does the angle in the FullOutput (https://sumo.dlr.de/docs/Simulation/Output/FullOutput.html) refer to the vehicle angle with respect to the road slope? I tried to set up a road stretch with a 0.02 (2%) & -0.02 (-2%) road slope by patching the network with z-coordinates. Since not all models incorporate elevation data (https://sumo.dlr.de/docs/Networks/Elevation.html), I have also selected the carFollowModel=”KraussPS”. All the angles in the FullOutput remained constant at 90 degrees. Is there an explanation for this result?

 

Any pointers are appreciated. Thank you in advance!

 

 

Warmest regards,

 

Addina

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