OICA is working on the same work packages as ISO. Up to today packages 1 and 2 have been investigated.

Ninety-seven vehicles within the OICA database were analyzed. Although all these vehicles don’t pose a concern in today’s traffic, meaning they are sufficiently recognizable by pedestrians, almost none of them fulfill the VOLPE requirements. Even sport cars that might be seen as obviously loud don’t satisfy the combinations of 3rd octave bands & SPLs as proposed. Therefore the proposal is to either reduce the number of minimum required 3rd octave bands but keep the VOLPE proposed SPL levels or to keep the proposed 3rd octave bands, however with reduced SPLs. It is also thinkable to prescribe a certain acoustic energy content that must be emitted with at least 2 of the proposed bands, but can also be distributed amongst more than 2.

The typical vehicle speed when driving in town is between 0kph and 30kph, so that AVAS would be active most of the time. This comprises the risk of driver and passenger annoyance from frequencies transmitting into the vehicle. The transmission loss between outside and inside of the vehicle decreases typically with 6dB per octave with frequencies becoming lower, so that low frequency content is difficult to be attenuated and can only be realized by adding mass in form of insulation material. Below 400Hz it is almost impossible to depressed sound to a level that will not be audible for vehicle passengers.

EVs are designed under specific light weight aspects so to enable longer driving ranges. Additional insulation material necessary to reduce noises from AVAS penetrating into the passenger compartment would jeopardize these design strategies. To overcome this, it is essential to restrict AVAS sounds to a level in SPL as well as to octave bands that are acceptable for the driver and the passengers to avoid distraction, annoyance and rejection.