Not clear from this article whether this will need to be retro-fitted to Roadsters. "Quiet" Electric Cars Will Sound Alerts Under Rule - Bloomberg Is any of this new? It seems like we've seen most of the "request for input" material before. This part at least seems like a new development: The "note" is this: http://www.nhtsa.gov/staticfiles/rulemaking/pdf/QuietCar-noi-draft.pdf P.S. Moderators, sorry, I realise this overlaps with this thread, should have posted there, please merge if possible.