D'oh
This seems like a massive waste of time, and a bit of a step back tbh.
1) Blind people will have a friend, guide dog, or use the crossing to get across safely. Does the US have bumps in the pavement like us?
2) Surely just moving (tires etc) will make electric cars more noisy than bikes now?
3) Remember that youtube video of a road playing music? Couldn't they install things at crossings so cars made a slight 'note' as they approached. Maybe 3 notes, getting higher pitched the closer they get.
Point 3 is important because this tech shouldn't be in cars (if needed at all). It should be in the environment or attached to the people who need it. Being in cars will lead to all sorts of problems, maybe even lawsuits because someone's car didn't make the right noise at the right time.
Also, how on earth is "location information to those who hear them" going to work?
Car: Beep! I am 50m away from you.
Me: Phew.
*Bump*
Car: Not you, that other guy.
p.s. For the record, I am blind in one eye. Hopefully I'll never be fully blind, but if that ever happens, I'd still take the peace and quiet over molly-coddling levels of safety.