## 3 Results  
Figure 5 shows the boxplots of Wm-weighted acceleration measurements at the six measuring points. The observed differences are mainly due to different housing conditions/characteristics and differences in velocity levels of trams per each measuring point. However, all peak values (except measuring Point 2) are slightly above the noticing level outlined by the Austrian standard ([48]). The variability at each point is also noticeable in terms of human perception. Overall, mean peak acceleration levels of \"New Trams\" are a bit higher than those from \"Old Trams\" at most measuring points (see Table A1 in the Appendix A). The \"fast\" time weighting (as used in the German standard) indicates that a slight underestimation of (potentially noticeable) peak exposure can occur with the time weighting \"slow\" (see Table A1 in the Appendix A). As the sound analysis revealed strong low frequency components and the classical A-weighting curve is known to underestimate this acoustic feature and may lead to incorrect assessment of the true disturbance of the exposed people [49], we analyzed the difference between the A-weighting and the C-weighting as recommended by DIN 45680 in such cases [50]. The observed large difference between A- and C-weighted levels (Table 1) indicates that a dBA-assessment may indeed not be an appropriate estimation of the actual perceived exposure. Figure 5: Vibration measurement results for each measurement point—compared with the Austrian Standard. Figure 8 shows a comparison of a passing A- and C-weighted sound pressure level of the same \"new tram (type Variobahn)\" calculated by Fast Fourier transform algorithm over a time of 1 min. Especially at lower frequencies, a significant difference in the sound pressure levels is noticeable and points to the importance of these frequency spectra for assessing the annoyance and sleep interference potential of the studied tramways. Additionally to the classical acoustic analysis, psychoacoustic parameters were used for detailed investigation. Results revealed a high variability in loudness and roughness at different locations and tram types. No systematic difference was observed with parameters like tonality and fluctuation. Figure 9 shows the N5 percentile loudness level for all passing tramways at each measuring point and Figure 10 for the three tram types in use. Both Figures 9 and 10 indicate a perceptually relevant variability for the psychoacoustic parameter loudness across the locations and tram types. The data of Figure 10 show a significant difference in loudness values between the \"new tram (Variobahn)\" and the \"old tram (CityRunner)\" (Mann-Whitney U test--\(p\)-value: 2.574 \(\times\) 10\({}^{-15}\)). Loudness values were calculated based on ISO 532 B for a diffuse sound field. The latter shows also a smaller variability of the loudness distribution. Note: An increase in median song from one to two means doubling of perceived loudness. As the spread goes from below one to five a substantial variation in the loudness of the Variobahn pass-by is therefore a perceptually relevant change. Figure 8: Pass-by sound pressure level of the same “new tram (type Variobahn)” calculated by Fast Fourier transform algorithm: (**a**) A-weighted signal; and (**b**) C-weighted signal. Figure 9: Loudness N5-Percentile in (soneGD) at each measuring point for all passing tramways. Figures 11 and 12 show an even higher variability for the psychoacoustic parameter roughness for several locations--with very high values at Point 3. Figure 12 points to the substantially larger variability in roughness of the \"new tram (Variobahn)\", as well as significant higher values compared to the \"old tram (CityRunner)\" (Mann-Whitney U test--\(p\)-value: \(1.239\times 10^{-11}\)). Loudness values were calculated based on Hearing Model after Sottek for a diffuse sound field [51]. Note: The perceptual threshold for roughness is slightly below 0.1 asper.