I&#x27;m not so sure.  I think the big difference it would make to have cars talking to each other is that they can all know where the other (within a local range) is heading, make interchanges more optimal.<p>A lot of traffic congestion happens because we have nothing but (too-infrequently-used) turn signals to indicate our intentions.  If all the cars knew where they were going at an interchange, you could at least optimize the flow.<p>Of course, there is _no_ solution when there are just too many cars trying to fit on a road that can&#x27;t handle it.  And that&#x27;s probably 80-90% of the problem anyway :(