Stuff like this is why I believe that level 4 autonomy within the next decade is quite the lofty goal and level 5 is completely out of the question. For exampl

Stuff like this is why I believe that level 4 autonomy within the next decade is quite the lofty goal and level 5 is completely out of the question. For example, in WA State, you can cross at any unmarked crosswalk which is defined as any intersection (plus a few non-intersections), unless there is a sign explicitly disallowing crossing. I wouldn't know how to accurately estimate this, but there are probably over 100k unmarked crosswalks in Seattle alone (most of which are ignored completely by humans). The pedestrian's responsibility is to not enter the roadway without enough time for a car to stop. The car's responsibility is to stop once the pedestrian signals intent to cross. Signaling intent does not require waiting at the edge of the roadway...merely walking towards the roadway while on the sidewalk is considered signaling intent to cross. What this effectively means is that the car must do far more than understand pedestrian behavior in crosswalks. It must understand the periphery of the road...not just the pedestrians it can see, but the pedestrians it can't. Most speed limits are actually too high to take into account legal pedestrian behavior. The speed limit is merely an upper limit; driving too fast for conditions can always override the speed limit as a factor in an accident. This means that trees, buildings, etc., that obscure view of and behavior of pedestrians on the sidewalk implicitly lowers the speed at which cars can drive on that road. Now today we essentially get away with favoring the driver. The driver can assume that they were acting reasonably by driving the speed limit, and we can say that the pedestrian was out of line by walking too fast out into the street, and most situations are resolved blindly based on testimony with no evidence. But the risk model of autonomous cars is different. The manufacturer is gonna be on the hook, not the driver, and the car needs to be able to obey the letter of the law with a higher burden of proof and with dozens of sensors recording the situation. As we can see from this paper, pedestrian recognition is still a hard problem. It's hard in the engineering sense, and the mathematical sense. But cars don't need to just recognize pedestrians...they need to recognize and understand the context in which a currently invisible pedestrian could appear in the near future. And perhaps more importantly, they still need to solve the problem of instantaneous path planning in a 2d space with a dynamically changing 3d obstruction model consisting of far more than just pedestrians. It's easy to look at the past and say we've made rapid progress in the past so we'll make rapid progress in the future...but in the process of maturing a technology we regularly see exponential progress in the beginning and asymptotic progress near the end. This is going to be very difficult.