No, they are not. You just need a "ton" (a lot) of different kinds of sensors and make the system more reliable than human drivers (less accidents - no need to get 99.9999% error rate). Considering that:
self-driving cars should not be a hard problem [they need to "beat" (be safer) "average human" on a road, not Michael Schumacher]. A hard problem would be making quantum computing really useful (at least for me).