There's only two systemic problems in the current road system that I know of: traffic jams, and the fact that increasing road capacity increases road traffic (and therefore doesn't reduce the potential for traffic jams). They're entirely due to the behavior of human drivers (given the surrounding circumstances in part too, of course).

Are other systemic problematic effects known in the current road transportation system? Notably, are there any systemic effects that lead to increasing speed and accidents, rather than traffic jams (not that traffic jams don't cause accidents, since human drivers are running too fast, not expecting jams).

It seems obvious that the two systemic problems above, won't occur with intercommunicating robotic cars.

It would be "fun" to discover new systemic epiphenomenon with robotic cars, but I would expect them to be more discreet and even less "catastrophic".