Methods of Gently Notifying Pedestrians of Approaching Objects when Listening to Music Yuki Sakashita Yoshio Ishiguro Kento Ohtani sakashita.yuki@g.sp.m.is.nagoya- ishiy@acm.org ohtani.kento@g.sp.m.is.nagoya- u.ac.jp Nagoya University u.ac.jp Nagoya University Tier IV, Inc. Nagoya University Nagoya, Aichi, Japan Nagoya, Aichi, Japan Nagoya, Aichi, Japan Takanori Nishino Kazuya Takeda nishino@meijo-u.ac.jp kazuya.takeda@nagoya-u.jp Meijo University Nagoya University Nagoya, Aichi, Japan Tier IV, Inc. Nagoya, Aichi, Japan ABSTRACT Many people now listen to music with earphones while walking, and are less likely to notice approaching people, cars, etc. Many methods of detecting approaching objects and notifying pedestri- ans have been proposed, but few have focused on low urgency situations or music listeners, and many notifcation methods are unpleasant. Therefore, in this work, we propose methods of gently notifying pedestrians listening to music of approaching objects using environmental sound. We conducted experiments in a virtual environment to assess directional perception accuracy and comfort. Our results show the proposed method allows participants to de- tect the direction of approaching objects as accurately as explicit notifcation methods, with less discomfort. CCS CONCEPTS • Human-centered computing → Auditory feedback. KEYWORDS Auditory Display, Directional Information Presentation, Sound Lo- calization, Environmental Sound ACM Reference Format: Yuki Sakashita, Yoshio Ishiguro, Kento Ohtani, Takanori Nishino, and Kazuya Takeda. 2022. Methods of Gently Notifying Pedestrians of Approaching Objects when Listening to Music. In The Adjunct Publication of the 35th Annual ACM Symposium on User Interface Software and Technology (UIST ’22 Adjunct), October 29-November 2, 2022, Bend, OR, USA. ACM, New York, NY, USA, 4 pages. https://doi.org/10.1145/3526114.3558728 1 INTRODUCTION More people are listening to music using earphones or headphones while walking, reducing awareness of their surroundings [12]. Al- though functions that capture external sounds (e.g., ambient sound Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for proft or commercial advantage and that copies bear this notice and the full citation on the frst page. Copyrights for third-party components of this work must be honored. For all other uses, contact the owner/author(s). UIST ’22 Adjunct, October 29-November 2, 2022, Bend, OR, USA mode [8]) are widely used to address this problem, it remains dif- cult to perceive the approach of people, bicycles, or automobiles when listening to music, resulting in obstruction of or collisions with, other users of roads and sidewalks. Many methods have been proposed for detecting surrounding objects and notifying pedestrians of their approach. However, some are unsuitable for detecting quietly approaching objects [13], while others require additional devices for notifcation by tactile stim- uli [2, 6]. Many are designed for urgent situations and use jarring notifcation sounds like beeps [5], which may be annoying in non- emergency situations. Furthermore, the accuracy of directional perception when using less intrusive sounds during music listen- ing has not been evaluated. Some methods tweak the music itself, afecting the music listening experience [3, 4, 10]. Our end goal is to develop a device that allows pedestrians to enjoy music to the maximum, safely and without disturbing other trafc. To achieve this goal, we propose detecting approaching ob- jects and varying the notifcation method according to the situation, giving gentler notifcations in less urgent situations. In this poster, as the frst step, we proposed methods to present environmental sounds from only the direction of an object approaching with envi- ronmental sounds blocked and made the following contributions. • Verifcation of the directional perception accuracy of several environmental sound notifcation methods during music listening, which has not been evaluated. • Comparison of subjective evaluations between the proposed and explicit notifcation methods for elements that could be perceived as unpleasant when walking during music listen- ing. We synthesized these results and investigated a method of notifca- tion that balances less discomfort and accuracy in perceiving the direction of approaching objects during music listening. 2 EXPERIMENT © 2022 Copyright held by the owner/author(s). We conducted the experiments to verify the appropriateness of the ACM ISBN 978-1-4503-9321-8/22/10. https://doi.org/10.1145/3526114.3558728 proposed methods for gently warning pedestrians.