I'm not condoning the actions of the biker on the sidewalk and am not defending his actions, but the driver of the vehicle was making a left which means traffic was coming from the right and the bicyclist came from the right also. I still think that expecting the bicyclist on the sidewalk to follow vehicular traffic direction is a stretch though. For instance, what do you do with runners on the sidewalk since they are often moving faster than a bicyclist?