I was riding my monowheel yesterday, on a trail, where people walk, bike, ride all sorts of contraptions. Here is what I can say about trying to predict what anyone does:
as long as a person is riding something, he is paying infinitely more attention than someone who is just walking, standing there. I was closing in on a couple of girls, they walked in front of me in the same direction, so they didn't see anything happening behind them, they walked on the right side of the road, so this is all good, all of a sudden one of them decides she wants her picture to be taken (the other one took it). So what does she do? She streak across the path, without stopping to think for a microsecond, without looking sideways even, never mind behind her. She crosses the path and strikes a pose, the other one turning to take her picture. Lucky for me, I was still a few meters back when she did that. I was going to pass them on the left (this is the opposite side of the path clearly, people bike and walk both ways on it). I rode between them. When I close on anyone from behind I either have enough speed to pass them in a fraction of a second on the left side or I tell them to watch for me, passing on the left. I imagine that we could have actually collided, but she would have collided with anyone, a bike or a pedestrian walking slightly faster, the only difference would have been the degree of damage. She would have been thrown, had I hit her, I had some protection, she obviously didn't have any.
There is nothing that can be done, you cannot control people's motion, I mean we cannot install 'self driving' into people's heads. They turn into you on highways, they don't look and do all sorts of things, oblivious about the surroundings completely, always amazed that something actually happens after they do something like that, as if life is supposed to protect them from every stupid thing they do, as if they are the only ones in space and there is nothing around them, nothing moving in any direction at all.
Beside the obvious problem of privacy invasion with systems like this, the reality is that there is no amount of technology that can save people from their own lack of thinking.