Influence of an artificially produced stationary sound of electrically powered vehicles on the safety of visually impaired pedestrians

Road traffic noise is the most annoying form of environmental noise pollution. The enforcement of using artificially generated sound for electrically powered vehicles is currently on the rise. In this regard, it is important to know if an additional stationary sound could be conducive to earlier detection. The aim of this project was to gather information on the influence of artificially generated stationary sound with an Acoustic Vehicle Alerting System (AVAS) of electrically driven vehicles on the safety of other traffic participants. The stationary sound of an electric vehicle denotes a sound corresponding to the idling noise of a conventional combustion vehicle. It indicates that a vehicle is stationary (v = 0 km/h) but the engine is running. Furthermore, the aim was to be investigated whether a stationary sound can contribute to the prevention of accidents. Various safety-relevant traffic situations, different stationary sounds and also driving sounds were used for this purpose. However, the question of whether a stationary sound would improve road safety for visually impaired pedestrians has not yet been addressed. The results of the study show that not every stationary sound in any driving situation leads to a better detection. Some stationary sounds show significant effects regarding the detection performance. Both laboratory tests and field tests have shown that there are stationary sound combinations which enable an earlier detection. Furthermore, an inappropriate stationary sound can also lead to a later detection. It has been found that clear differences e.g. due to level differences or frequency shifts between driving and stationary sound could lead to earlier detection.