Hello Florian, Well, obviously, I did not explain it properly. Vehicular emissions mainly depend on the acceleration and the speed, with acceleration being the major influence. As SUMO is a microscopic model where the vehicles’ speed and acceleration are known, this information is used in all of SUMO’s emission models. But within the original HBEFA, no dependency between accelerations and emissions exists. HBEFA is an inventory models which only gets vehicle types (the vehicle fleet in fact), the mileage, and the traffic state as inputs – and the slope. Now slope can be transformed into acceleration – the power needed to climb is physically of the same type as the power needed to accelerate. And that has been done when transferring HBEFA-values into SUMO’s HBEFA-based emission model. This means SUMO uses the acceleration and the speed though acceleration was not given in the original HBEFA.
Now I must admit that I do not know why your values differ only by such small values. I have never worked with elevations in SUMO. Maybe someone else can answer this. Sincerely, Daniel Von: Florian Schnepf <[email protected]> Gesendet: Samstag, 19. August 2023 15:40 An: Krajzewicz, Daniel <[email protected]>; [email protected] Betreff: Aw: AW: [sumo-user] HBEFA Emission Model Hi Daniel, What happens when there is no information about the slope? I have made some tests with one network with increases and one without, as well as two HBEFA emission models. The results show that there is very little difference on average. * Diesel vehicle: With elevation: 22.319 g without elevation: 22.495 g * Fuel cell vehicle: With elevation: 6.374 g without elevation: 6.522 g I would expect consumption to be higher with elevation than without. Does this mean that the information about the slope does not contribute to the calculation of the consumption, since it replaces the influence of acceleration? Best regards Florian Gesendet: Montag, 14. August 2023 um 10:54 Uhr Von: [email protected]<mailto:[email protected]> An: [email protected]<mailto:[email protected]> Cc: [email protected]<mailto:[email protected]> Betreff: AW: [sumo-user] HBEFA Emission Model Hello Florian, well, no. HBEFA has the information about the influence of slope on emissions. On the other hand, as HBEFA uses (macroscopic) traffic states, it does not use (microscopic) acceleration. So, when deriving emissions from HBEFA, we used the slope information for replacing the missing influence of accelerations. Sincerely, Daniel Von: sumo-user <[email protected]<mailto:[email protected]>> Im Auftrag von Florian Schnepf via sumo-user Gesendet: Montag, 14. August 2023 10:51 An: [email protected]<mailto:[email protected]> Cc: Florian Schnepf <[email protected]<mailto:[email protected]>> Betreff: [sumo-user] HBEFA Emission Model Hello, I read in a paper about the emission models that the HBEFA model does not depend on acceleration and therefore the slope is used for compensation. I do not understand how this is meant. Can someone explain to me how this was implemented? Thanks a lot Best regards Florian
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