It may not be that interesting for cars, but it is for trucks. A friend of mine is working on a similar system for trucks. The point there is that the group of trucks would actually behave as a train (and need only one driver, or at least the others could rest). The trucks this way could also drive closer to each other sparing on gas.

On the what happens when the leader car hits an elk scenario - the leader vehicle could (and probably does) transmit its own parameters (speed, acceleration, etc.).