In vehicles, noise and seat vibrations can be perceived by the driver, depending on their signal properties, as annoying or unpleasant. Because perception is a complex process, it is necessary to consider both types of stimuli at the same time to assess annoyance in such situations. A perception experiment was carried out to investigate the interaction between simultaneous noise and seat vibrations, as well as the influence of seat vibration frequency in vehicle situations. For the experiment, acoustic and optical stimuli such as seat vibrations were recorded in a mini excavator and a refuse collection vehicle from the view of the driver. The recordings were prepared for plausible reproduction in a laboratory experiment. The participants of the experiment were presented with two different vehicle scenes with simultaneous noise, seat vibrations and visuals. The average total levels of vibration and noise, as well as the vibration frequency ranges of the various vehicle scenes, were varied. The results suggest that an interaction effect between noise and vibration should be accounted for when assessing total annoyance in such situations. Models for the prediction of the relative total annoyance causes of variations in noise and vibration levels were developed.

Noise and whole-body vibrations (WBV) inside commercial vehicles can lead to annoyance and reduced comfort. As a result, negative effects on the driver can occur even below the legal exposure limits. In order to understand the annoyance perception and the interaction between noise and WBV, two perception experiments were conducted. For both experiments, recorded signals inside different commercial vehicles were used. Sound pressure and acceleration levels varied. In addition, the frequency content of the recorded vertical seat vibrations was reproduced in different modified variants. The varied parameters (sound pressure level, acceleration level and vibration frequency) were investigated within a three-factorial experimental design. It was found that noise and vibration levels, as well as the vibration spectrum, had a significant effect on total annoyance. Furthermore, an interaction between noise and vibration levels in both experiments could be observed. The results show that for the highest noise level, changing vibration exposure influences annoyance ratings less than the lowest noise level. The results also show that despite the same Wk-weighted RMS level of the WBV according to ISO 2631-1, vibration spectra with sinusoidal components or narrowband vibrations below <10 Hz were significantly perceived as more annoying during a ride in a vehicle.