I started work on what I called ACCP (Advanced Car-to-Car Protocol) in 2004. From the overview:
ACCP is a protocol for communication between two moving vehicles, to assist in making the driving task more efficient, and to make driver intentions explicitly known to those around them. The capabilities of this system advance upon the limited “communications” available today (turn signals and brake lights). Computers within each participating vehicle can talk wirelessly to vehicles near (adjacent) to them.
My intent was for things like signaling "I am looking for an address and don't see it" while driving slowly, and co-operatively determining target speed to aid in passing situations on single lane roads. I was wondering how long it would be before someone started doing something like this (although Michigan is more skewed to safety).
Over the last few years I've second-guessed myself on exactly how much of this I would really want to see. The opportunities for abuse are many and getting the implementation right would be difficult.
FORTRAN is not a flower but a weed -- it is hardy, occasionally blooms, and grows in every computer. -- A.J. Perlis