The rise of electric drive vehicles (EVs), from fully electric to hybrid vehicles, has created an unprecedented noise problem in fact, EVs are too quiet. At low speeds, EVs make little noise compared to combustion engines, which can create potential safety hazards when pedestrians fail to notice vehicles idling nearby or approaching.
Fewer emissions, quieter vehicles
Public awareness of global climate change and limited energy resources is at an all-time high, creating a strong demand for energy-efficient electric drive vehicles that reduce CO2 emissions. These electric drive vehicles employ an electric motor during low-speed driving, making them extremely quiet when compared to the familiar rumble of a typical combustion engine. However, this potential selling point also makes EVs less noticeable by pedestrians.
Added sound makes low-speed driving safer
To address this public safety issue, the United Nations has recommended that all EVs should be equipped with sound-emitting devices (“acoustic vehicle alerting systems”) to ensure that pedestrians hear approaching vehicles. In 2016, Japan’s Ministry of Land, Infrastructure, Transport and Tourism mandated that all Japanese EVs be equipped with this technology. The policy focuses on sound made in the range of 20 km/h or slower, where the greatest difference between EVs and combustion engines can be measured.
Education can help change pedestrian behavior
Previously, sound emissions were measured in a 7.5-meter radius, in accordance with conventional noise regulations. However, because ambient noise may skew results, the measurement distance was shortened to a radius of 2 meters. This method for measuring sound in idling and low-speed vehicles was recently issued as a Japanese Industrial Standards (JIS), as well as a new standard for indoor sound measurements able to produce comparable indoor test results. Both of these new standards are consistent with international standards.
METI hopes that these JIS testing methods will help increase public understanding of EV sound and safety hazards, and help create more pedestrian-friendly products.