This project performed research to support the development of potential specifications for vehicle sounds, (i.e., audible countermeasures) to be used in vehicles while operating in electric mode in specific low speed conditions. The purpose of the synthetic vehicle sound is to alert pedestrians, including blind pedestrians, of vehicle presence and operation. The project developed various options and approaches to specify vehicle sounds that could be used to provide information at least equivalent to the cues provided by ICE vehicles, including speed change. Acoustic data from a sample of ICE vehicles was used to determine the sound levels at which synthetic vehicle sounds, developed as countermeasures, could be set. Psychoacoustic models and human-subject testing were used to explore issues of detectability, masking, and recognition of ICE-like and alternative sound countermeasures. Data were used to develop potential options that could be pursued to develop specifications for synthetic vehicle sounds. Project results indicate that vehicle detectability could potentially be met through various options including: recording(s) of actual ICE sounds; synthesized ICE-equivalent sounds; alternative, non-ICE-like sounds designed for detectability; and a hybrid of the options listed above. (Author/publisher)
Samenvatting