This study explores the effectiveness of a multisensory relaxation program developed for a high performance coupe interior by a German auto manufacturer. There is a growing need to introduce sensory-rich cabin experiences that bring about stress alleviation coupled with improvement of attention. The aim of this research is to evaluate whether auditory, visual, and tactile stimuli can facilitate relaxation in occupants following a high-arousal driving task.

A total of thirty-three participants were subjected to four therapy program conditions in a counterbalanced Latin Square order: no stimulus (control), auditory-only, auditory + visual, and auditory + visual + tactile (vibratory) stimuli. A custom test buck was built for the therapy activities, emulating the interiors of a sports coupe. The therapies were preceeded by a driving simulation stressor. Physiological data such as electrodermal activity, pulse rate, and skin temperature were collected through a wearable device, while subjective responses were collected via questionnaires. A psychomotor vigilance task (PVT) was also paired with the questionnaires to measure response times.

Physiological data analysis reveals no statistical differences between the four therapy conditions. PVT reaction times show minor improvements post-therapy, aligning with expectations. However, subjective data indicates clear preferences among participants. The complete therapy was most frequently rated as effective, though many complained about visual overstimulation. In contrast, the audio-only condition was perceived most balanced. Notably, participants suggested an audio-tactile configuration omitting the visual component.

These findings show that while objective data is still inconclusive, subjective feedback support such multisensory integrations in automotive interiors, particularly during idle EV charging phases or pre/post performance driving.