## 7 Discussion and Outlook  
The measurement series presented in Sections 5 and 6 lead to the following six main conclusions that extend or question the existing literature. Firstly, the vehicle weight does not seem to have any noticeable impact. That is what measurements for a weight difference of up to one quarter of the absolute weight indicate. This contradicts the literature presented in Section 1. Secondly, the accelerated noise increase depends on the applied torque on the wheels rather than the vehicle acceleration. This assumption is reasonable since in the cases where torque is only applied on two rather than four wheels, the slopes of regression curves are larger and increase more rapidly. This results in two louder sources that lead to an absolute louder noise than four less noisy sources. The maximum recorded increase in SPL due to acceleration lower than \(2\,\mathrm{m}\,\mathrm{s}^{-2}\) was recorded with \(1.04\,\mathrm{dB}(\mathrm{A})\). Thirdly, some of the tires investigated in this research emit less noise for small accelerations compared to no acceleration. Fourthly, the rolling noise of mixed mounted tires can be approximated by averaging the rolling noise of the two measurements with according equal tires. In case of the accelerated noise and mixed mounted tires, the non-accelerated tire also has a small impact on the calculated regression curve. Fifthly, the rolling noise is impacted by the choice of vehicle up to an average absolute difference of approximately \(1\,\mathrm{dB}(\mathrm{A})\). Finally, the virtual tire change does seem to lead to overall good results with a slight restriction that the vehicle body shape seems comparable. Nevertheless, it is notable that the presented tire changes are only single runs that are compared. The fact that even these single, repeated runs can lead to very different SPL curves makes it assumable that the tire change generally works even better since, through trying to generate a validation run, some error is inserted in the algorithm. Overall, this research confirms that the virtual tire change works, and that at least for AWD the acceleration of tires does not have a large impact on the SPL relevant for certification according to UN/ECE Regulation No. 51 [2]. Figure 20: Tire change for MSHEV, tires measured while mounted on different EVs, pred indicating the EV used for the prediction. More research needs to be conducted to solve the question of why some vehicles lead to larger rolling noise. These topics might also be addressed on test benches, since in that way all environmental conditions could be standardised. In addition, more research is necessary to determine why some tires do not seem to fit the generalized accelerated behavior. Thereby, it is also necessary to validate that the torque leads to higher CODs than the acceleration. Conceptualization, M.L., F.G.; methodology, M.L. ; software, M.L. ; validation, M.L. ; investigation, M.L. ; data curation, M.L. ; writing--original draft preparation, M.L. ; writing--review and editing, M.L., F.G.; visualization, M.L. ; supervision, F.G.; project administration, M.L. All authors have read and agreed to the published version of the manuscript. This research received funding by Mercedes-Benz Group AG. The authors thank the Mercedes-Benz Group AG with the department overall vehicle integration NVH powertrain for their support. Additionally the authors thank [PERSON] from the department overall vehicle integration NVH carbody and chassis for always being available to discuss the ongoing research. The authors thank [PERSON] from the Karlsruhe Institute of Technology for valuable input and support. We acknowledge support by the KIT-Publication Fund of the Karlsruhe Institute of Technology. The authors declare no conflict of interest. [PERSON] is from Mercedes-Benz Group AG, the company had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.