The state of art of quiet road transport vehicle minimum noise requirement standards and regulations

Electric vehicles have the feature of being quiet when running, thus may led to high potential risk of traffic accident between cars and pedestrians. To avoid pedestrian injuries, many country tends to force auto manufacturers to equip their cars an acoustic vehicle alerting system for indication purpose. This paper intend to give a brief introduction of related standards and regulations developed or underway, deliver comprehensive comparison in technical aspects, and finally offers a broad view of the state of art of this realm.