What if an autonomous vehicle see a pedestrian walking towards the road in front of the car (X meters in front but on a collision course with the car)? It calc

What if an autonomous vehicle see a pedestrian walking towards the road in front of the car (X meters in front but on a collision course with the car)? It calculates that if the human continues this path, they will collide. Should the car slow down so that no matter what the car can stop if the human decides to run out in front of the car or assume that the human will stop? What if you change human to deer? Autonomous vehicles should never be in the situation of hitting something. They should always calculate ahead of time what could possibly move into their path. If there is an obstacle then the car should slow down sufficiently to prevent an accident no matter what happens. I realize that there are near unlimited use-cases that will have to be accounted for. How would it handle a squirrel that is just sitting in the road? Stop and honk? Would it ever go around the obstacle by moving into an oncoming lane if it's deemed safe? Should they program in the ability to recognize the difference between a piece of carpet that has fallen onto the road and a board with nails or should it stop in the middle of the street for both?