Auditory Alerts for E-scooters: Relationship Between Pedestrian Auditory Detection Rates and Alert Sound Level

Walton, Tim; Elias, Duarte S; Torija, Antonio J

Abstract

Electric micromobility has the potential to transform the urban transportation system by offering increased personal mobility, whilst reducing congestion and air pollution. Standing electric scooters (e-scooters) are considered as the most popular mode of electric micromobility on our streets today and have seen a significant rise in numbers in recent years, both as part of the shared-use paradigm and through private ownership. However, safety concerns have proved a barrier to public acceptance, with one key safety concern being that e-scooters emit very low noise levels, resulting in a higher perceived level of risk by pedestrians. The issue of electric vehicle audibility is well studied within the context of electric cars and regulations are now in place that stipulate minimum sound levels for electric vehicles (EVs). To achieve these minimum sound levels, Acoustic Vehicle Alerting Systems (AVAS) are used, which provide increased audibility for pedestrians at low speeds. Currently, there are no regulations for micromobility AVAS and research into this topic is limited. In this paper, we consider the development of an e-scooter AVAS by investigating auditory detection rates of e-scooter alert sounds as a function of alert sound level, environmental noise level and distance. A listening experiment was conducted whereby participants were required to identify AVAS signals within a simplified environmental noise spectrum, presented in a randomised yes-no procedure, for a range of e-scooter AVAS conditions and environmental noise levels. Psychometric functions were subsequently derived, resulting in an understanding of auditory detection probabilities as a function of AVAS level, environmental noise level and distance. The presented results are an important step in the understanding of e-scooter safety measures and help establish minimum sound levels for e-scooter AVAS going forward.

Citation

Walton, T., Elias, D. S., & Torija, A. J. (2023). Auditory Alerts for E-scooters: Relationship Between Pedestrian Auditory Detection Rates and Alert Sound Level. Applied Acoustics, 214, https://doi.org/10.1016/j.apacoust.2023.109683

• Journal Article Type: Article
• Acceptance Date: Oct 2, 2023
• Online Publication Date: Oct 10, 2023
• Publication Date: Oct 10, 2023
• Deposit Date: Oct 2, 2023
• Publicly Available Date: Oct 11, 2025
• Print ISSN: 0003-682X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 214
• DOI: https://doi.org/10.1016/j.apacoust.2023.109683
• Keywords: E-scooter; Micromobility; Sound Quality Metrics; Alert Sound; AVAS; Auditory Detection