3 ms·

How far ahead to the sensors work? Maybe there is lots of time at 100km/h. They certainly need to look far enough ahead to detect a stationary object in the roa

How far ahead to the sensors work? Maybe there is lots of time at 100km/h. They certainly need to look far enough ahead to detect a stationary object in the road and come to a complete stop, as does a human. A car coming towards you in the wrong lane at 100km/h is a different kettle of fish though (as it is for a human). Over here, the speed limit with road works is 40km/h

ineedasername 6y ago
In the US on highways the speed limit near construction generally drops from the usual 65mph/105kmh down to 50 or 55mph/85kmh. I think the federal reference is 45mph to 55mph, but in my experience it's usually at the highest level, 55mph, unless there's really active work with crew on the ground. If you're accustomed to 40kmh, I can only imagine how insane these speeds probably seem to you. (And I'm not saying you'd be wrong in that) Overall, the problem of course comes down to reaction speed. An attentive human with hands on the wheel might respond in 250ms. A computer obviously can respond faster. But some problems won't give you any more than that 250ms to respond. Situations where faster sensors or cpu are meaningless in giving the driver more warning because there is literally only 250ms from onset of stimulus to the time needed for a reaction if catastrophe is to be avoided. Meaning that if the computer can't respond without human intervention, an inattentive driver is screwed because their 250ms reaction speed was based on them already paying attention. To break it down in rough estimates: 1) The car detects & make its own assessment and raises an alarm. 1ms? 10ms?, It almost doesn't matter. 2) The human receives & registers the alert. This is the initial 250ms reaction time. 3) Only then can the real work begin: The human, from a cold start, needs to take in the entire situation and understand what's going on. This is more than just reaction speed. This is task switching, which is cognitively more costly, especially for un-practiced tasks, and the task here is rapid analysis & synthesis of a panic inducing situation that most people never experience. 750ms is probably about right, based on research that shows the cognitive burden of task switching can be even higher [0] So, a full 1000ms, a full second. This is way, way too slow. As I said at the beginning, there are moments driving where that 250ms is required to avoid catastrophe. When those situations arise then there is simply not enough time for the car to get help of an inattentive driver to respond. It's simply not possible. Either the car makes the decision, or the human has just enough time to go wide-eyed before it's over. Basically the only situations where the car's notifications can facilitate meaningful human response are those that can be foreseen at least a full 1000ms in advance. Certainly this encompasses a lot of difficult scenarios, but not many of the most dangerous ones. Any time a split-second decision saved the life of a driver? That same driver, if inattentive when the car's alert comes in, is now dead. There is simply no self-driving car that that can safely allow human inattention until the car can make a whole lot more of its own decisions. In the meantime, if overzealous marketing & breathless hyperbole don't continue to oversell these capabilities, then computer-assisted driving by attentive drivers should greatly improve safety. [0] https://www.semanticscholar.org/paper/Task-switch-costs-subsequent-to-cue-only-trials-Swainson-Martin/670ad5e399d4680fe9a1dbdb2584e13f59cc9b6b https://www.semanticscholar.org/paper/Task-switch-costs-subs...

ineedasername 6y ago

In the US on highways the speed limit near construction generally drops from the usual 65mph/105kmh down to 50 or 55mph/85kmh. I think the federal reference is 45mph to 55mph, but in my experience it's usually at the highest level, 55mph, unless there's really active work with crew on the ground. If you're accustomed to 40kmh, I can only imagine how insane these speeds probably seem to you. (And I'm not saying you'd be wrong in that) Overall, the problem of course comes down to reaction speed. An attentive human with hands on the wheel might respond in 250ms. A computer obviously can respond faster. But some problems won't give you any more than that 250ms to respond. Situations where faster sensors or cpu are meaningless in giving the driver more warning because there is literally only 250ms from onset of stimulus to the time needed for a reaction if catastrophe is to be avoided. Meaning that if the computer can't respond without human intervention, an inattentive driver is screwed because their 250ms reaction speed was based on them already paying attention. To break it down in rough estimates: 1) The car detects & make its own assessment and raises an alarm. 1ms? 10ms?, It almost doesn't matter. 2) The human receives & registers the alert. This is the initial 250ms reaction time. 3) Only then can the real work begin: The human, from a cold start, needs to take in the entire situation and understand what's going on. This is more than just reaction speed. This is task switching, which is cognitively more costly, especially for un-practiced tasks, and the task here is rapid analysis & synthesis of a panic inducing situation that most people never experience. 750ms is probably about right, based on research that shows the cognitive burden of task switching can be even higher [0] So, a full 1000ms, a full second. This is way, way too slow. As I said at the beginning, there are moments driving where that 250ms is required to avoid catastrophe. When those situations arise then there is simply not enough time for the car to get help of an inattentive driver to respond. It's simply not possible. Either the car makes the decision, or the human has just enough time to go wide-eyed before it's over. Basically the only situations where the car's notifications can facilitate meaningful human response are those that can be foreseen at least a full 1000ms in advance. Certainly this encompasses a lot of difficult scenarios, but not many of the most dangerous ones. Any time a split-second decision saved the life of a driver? That same driver, if inattentive when the car's alert comes in, is now dead. There is simply no self-driving car that that can safely allow human inattention until the car can make a whole lot more of its own decisions. In the meantime, if overzealous marketing & breathless hyperbole don't continue to oversell these capabilities, then computer-assisted driving by attentive drivers should greatly improve safety. [0] https://www.semanticscholar.org/paper/Task-switch-costs-subsequent-to-cue-only-trials-Swainson-Martin/670ad5e399d4680fe9a1dbdb2584e13f59cc9b6b https://www.semanticscholar.org/paper/Task-switch-costs-subs...