With respect to speed limits (and not stop signs, so this is explicitly a bit of a digression), it's also worth noting that sometimes you have to choose between

With respect to speed limits (and not stop signs, so this is explicitly a bit of a digression), it's also worth noting that sometimes you have to choose between "safe" and "legal" since most municipalities set speed limits which are not safe (the safest speed being the speed at which traffic naturally flows). So should a self-driving car (or human, for that matter) drive safely or legally?