How about an app that translates abnormal sounds to someone who is deaf.. Such as..
I hear water running.. (I've left the not water on for hours)
The toilet flushed (not good when you are home alone)
A knock on the door.
Frantic banging on the door
smoke detector beeping (Couldn't figure out why my dog was shaking)
Unidentified noise (db level)
Maybe for local trips, but if you are commuting daily and on the road for 1-2 hours a day, wouldn't you rather do something else? I would be happy to catch up on my sleep or do other tasks and let the vehicle drive itself. I hate the waste of time in commuting and would see this as an opportunity to regain it.