The single best thing we could do is clearer signs and road markings. As a bonus it also helps human drivers. Making them wireless helps very little because clear signs are some of the easiest things to recognise and for self-driving you need to recognise everything else on the road, or there's little point. So if you can't recognise signs reliably then there's no point trying the rest of the task because you already suck and should get good at that before you try anything else (which should be a hint about where Tesla's at if they still can't do it). What self-driving cars (and humans) struggle with are ambigious signs and road markings, and they both struggle more with dealing with identifying and predicting the behaviour of everything else on and near the road.

(And this is the actual conversation actual self-driving companies are having with governments around the world, but it doesn't tend to result in anything because 'just do what we should be doing anyway but better' tends not to result in sexy headlines or votes)