News articles on this topic tend to be less than worthless - an increasingly typical state of affairs. In this case the reason is quite direct: people are scare

News articles on this topic tend to be less than worthless - an increasingly typical state of affairs. In this case the reason is quite direct: people are scared of revolutionary technology, and especially self driving vehicles -- and nothing gets clicks like fear mongering. Don't believe everything you read, let alone parrot it. You'll also notice the paragraph in Waymo's report, which is typical: "Note that, while we have used, where applicable, the causes mentioned in the DMV rule (weather conditions, road surface conditions, construction, emergencies, accidents or collisions), those causes were infrequent in our experience. Far more frequent were the additional causes we have labeled as unwanted maneuver, perception discrepancy, software discrepancy, hardware discrepancy, incorrect behavior prediction, or other road users behaving recklessly." In other words, they ended up disengaging because of "emergencies", which your imminent hard braking would apply as - exactly 0 times.