For the netspit stuff I'd look at Phoenix.Presence works and see how that handles it with a CRDT. There are various ways of distributing things across nodes in Erlang/Elixir but maybe you'd need to build something.
I think you are right about the riak core stuff - you could probably keep track of cars using some sort of distributed hash and kill multiple cars if they were to ever spawn.
In fact a way of instantiating processes and finding them based on a CRDT is probably a pretty cool little project...
I think that's a cool idea. It would have the downside that error recovery could take a while though, depending on the permdown period, so during that time a driver would be stuck; while in a request-based system they can immediately try again and it would work (hit a different instance). But it might not be too bad.
I think you are right about the riak core stuff - you could probably keep track of cars using some sort of distributed hash and kill multiple cars if they were to ever spawn.
In fact a way of instantiating processes and finding them based on a CRDT is probably a pretty cool little project...