How cool would it be to able to verbally communicate with every other motorist while driving?
If someone cuts you off, you could let them know they're an asshat and they'll hear it! On the flip side, if your in an emergency situation, like your wife is in labor or something, you could use it to help clear traffic. You could compliment a guy on his brown turbo diesel wagon or laugh at the guy in his slammed ricer Cavalier.
It could make things safer in situations like merging, or when there is a hazard in the roadway.
This idea is completely impractical and could never work. But it's something to think about.
Here's something relevant for your time: