[saiya-jin]

Indeed, we don't get basic things like GPS signal 100% right 86400 seconds per day. Relying on some remote DB which can crash, be hacked, cut off from internet, down for maintenance etc will be a problem. Or car just losing data connection (like it happens with phones).

Its nice to dream about ideal future, but if lives rely on reliability, it either works 100%, or shouldn't.

[bluGill]

100% is stronger than we need - humans are not 100%. If we were there would be no crashes. Even sudden mechanical failure could just affect the one car and not cause others if humans were perfect. We just need to be better than humans.