How should an electric vehicle sound? User and expert perception

As electric vehicles are moving in on the automobile market, safety relating to acoustic perception is an important issue. It is a growing concern, particularly with respect to pedestrians, cyclists or visually impaired people. This can be addressed by adding sounds to the vehicle whilst at low speed. However, adding artificial sounds to an electric vehicle begs the question as to what kind of sound is appropriate. Appropriateness concerns technical specifications and is also linked to affective reactions of recipients of such a sound. Emotional reactions to 17 artificial exterior sounds for electric vehicles were investigated in an experimental setting with a total of 40 participants, 34 novice users and six sound experts. Word association was used to elicit emotional reactions to the different sounds. Novice users employ more characterrelated terms to describe the sounds, while experts use more composition-based words. Analysis of variance and conjoint analysis was used to analyze participants’ assessments of sounds according to two semantic scales (pleasantness and appropriateness). Considerable inter-individual differences in the ratings of pleasantness and appropriateness indicate a great diversity of opinion about the sounds. Novice users indicate their preference for the sound of the traditional combustion engine as a possible proposition. Whilst participants saw the necessity, there was generally little enthusiasm for adding sounds to electric vehicles. The contribution of the paper concerns the methodology to analyze the results of the experiment and implications for the design of sounds for electric vehicles.