If "traveling at 12 mph or slower" is the actual legal language, I would think that no sound when the vehicle is stopped would be OK, as it is obviously not "traveling" when it is not going anywhere.Yes, Rivian uses bird-like chirps for door opening / closing locking, but they can change with updates. For Halloween for example, the car could make owl noises with that update, and also includes on-screen Zombies (instead of people) when humans are passing the car + orange / amber lighting effects. Pretty wild what you can do with little updates and SW based on the way the tech is implemented.
Here is the reg:
The National Highway Traffic Safety Administration (NHTSA) requires that hybrid and light electric vehicles (LEVs) with four wheels and a gross weight rating of 10,000 lbs or less make a sound when traveling at 19 mph or less. This requirement is part of Federal Motor Vehicle Safety Standard (FMVSS) No. 141, also known as the "quiet vehicles" rule. The standard was established in December 2016 in response to the Pedestrian Safety Enhancement Act of 2010, which mandated that EVs make noise to help prevent pedestrian injuries. The NHTSA estimates that the rule could prevent 2,400 pedestrian injuries each year.
The artificial engine sound that EVs make must be at least 56 decibels (dBA) within 2 meters when the car is traveling at 12 mph or slower, and no more than 75 dBA. The sound increases when the car speeds up and decreases when it slows down to simulate the sound of an internal combustion engine (ICE) car. At higher speeds, tire and wind noise are usually the main sources of a vehicle's noise, so the sounds of EVs and ICE vehicles are similar.
In 2019, the NHTSA issued a notice of proposed rulemaking (NPRM) to amend FMVSS No. 141 to remove the numerical limit on compliant sounds. The NHTSA also loosened language in the rule that restricted sound variation between different makes, models, and trim levels
If it's allowed, I'd like to be able to choose from a few sounds. Personally, I think a quite ICE motor sound makes sense when around people, as everyone knows what that sound means. It should "rev", which is also a audible clue people use to track cars. This would be best for the blind as well. When not driving around people, I'd also prefer some type of nature sound or, of course, no sound at all.
Also, I recall an thread on the Ioniq 5 forum where someone rigged up a remote control for their pedestrian noise using some gadget from Amazon. That was possible because there is a fuse that controlled the sound and only the sound. Default it to "on". When you head away from people, just click the remote to "off".