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Comment by ionforce | Hacker News Reader

Isn't the point of smart vehicles that they have superhuman reaction speed?

e=mv2, whether or not the driver is a superhuman robot or a human.

This means that there's a fixed distance from which the optimal driver can stop a car doing xmph. Yes, an autonomous vehicle has a faster reaction time* to begin the stop, but no matter the reaction time, a stop cannot be instantaneous from any substantial amount of speed.

If it takes 20 feet to stop a car doing 20MPH, it will take 80 feet to stop a car doing 40mph. If there's a human between the initial brake point and 80 feet from it, that human will be hit, no matter who or what the driver is.

Tempe police have said that the car didn't brake ("significantly") prior to the collision[1]. So it does not seem that the car reacted optimally but simply had too much speed to halt in time.

[1]http://www.phoenixnewtimes.com/news/cops-uber-self-driving-c...

I haven't any insight to whether or not the car did or didn't attempt to brake, but it's necessary to respond to the "superhuman reaction speed" remark as, even if the reaction speed is superhuman, that doesn't necessarily mean that it's enough.

Accidents can still occur even if the car is perfect.

> to begin the stop

It, or the driver, could do more than just stop though. You can change directions, even at 38mph.

Then we have to get into other questions, would I as a driver willingly sideswipe a car next to me to avoid hitting a pedestrian? Is it reasonable to expect an AI to make the same value decision?

It's not unknown for people to crash and burn to avoid hitting squirrels. And with modern airbag systems, it's arguably safer for all concerned for cars to risk hitting poles, and even trees. But on the other hand, once leaving the roadway there's the risk of hitting other pedestrians.

This is a major ethical decision to make. What if the airbags don't open up. What if there are other unseen things to crashing one's car to save somebody else's life. I honestly believe given a split second reaction time, any decision made by a human should be considered right.

An algorithm however is a different deal, what should happen is already decided in an algorithm, so in some way its already settled who gets killed.

When driving on surface streets, I do my best to track what's happening wherever in front, not just on the roadway. Given all the sensors on a self-driving car, why can't it detect all moving objects, including those off the roadway, but approaching?

Its all about what things are hiding behind the opacity. Blind spots are one thing, but if you jump right in front of a car out of nowhere from a place totally invisible to a sensor, its a totally different case.

You can't avoid what is hiding.

Yes, of course. But that isn't what happened here, right? A woman and bicycle on a median should have been quite obvious. I don't even see substantial landscaping on the median.[0]

0) https://www.nytimes.com/2018/03/19/technology/uber-driverles...

It appears that's pretty close to what happened here.

http://fortune.com/2018/03/19/uber-self-driving-car-crash/

We can try. In theory, each self-driving vehicle doesn't have to drive in isolation; they can be networked together and take advantage of each other's sensors and other sensors permanently installed as part of the road infrastructure.

That would increase the chance a particular vehicle could avoid an accident which it couldn't, on its own, anticipate.

Also the fact that most people now carry tracking devices. And that more and more, there are cameras everywhere. So there's potential for self-driving vehicles to know where everyone is.

It would be much safer if all roadways with speed limits over a few km/h were fenced, with tunnels or bridges for pedestrian crossing. Arguably, we would have that now, but for legislative efforts by vehicle manufacturers many decades ago. Maybe we'll get there with The Boring Company.

TL;DR: Nope.

"Most people" (which is, in reality, "most of my geek friends with high disposable income") shifts to "everyone" by the end of sentence. Also, my devices seem to know where I am...within a few city blocks: I do not like your requirement of always-on mandatory tracking, both from privacy and battery life POVs.

Even worse, this has major false negatives: it's not a probation tracker device - if I leave it at home, am I now fair game for AVs? And even if I have it with me and fine position is requested, rarely do I get beyond "close to a corner of X an Y Street," usually the precision tops out at tens of ft: worse than useless for real-time traffic detection.

Moreover, your proposal for car-only roadways is only reasonable for high-speed, separated ways; I sure hope you are not proposing fencing off streets (as would be the case here: 50 km/h > "a few km/h", this is the usual city speed limit).

OK, it was a dumb idea. Mostly dark humor. Reflecting my concerns about smartphones etc tracking location. But I do see that GPS accuracy for smartphones is about 5 meters,[0] which is close to being useful to alert vehicles to be cautious. And yes, it wouldn't protect everyone, and would probably cause too many false positives. And it's a privacy nightmare.

Some do argue that speed limits for unfenced roadways within cities ought to be 30 km/h or less. And although fatalities are uncommon at 30 km/h, severe injuries aren't. I live in a community where the speed limit is half that. But there's no easy solution, given how prevalent motor vehicles have become. Except perhaps self-driving ones.

0) https://www.gps.gov/systems/gps/performance/accuracy/#how-ac...

Edit: spelling

The promise of self-driving cars is (was) that they’re much better than humans at predicting he behavior of other moving entities. A pedestrian doesn’t suddenly materialize on the road in front of the car. It comes from somewhere and the radar could have detected it (even « in the shadows »), and slowed down in anticipation of an uncertainty.

Or maybe it couldn’t, but then the whole « narrative « of the experiment is in serious jeopardy.

> whole « narrative « of the experiment is in serious jeopardy.

Not really. Self driving cars are supposed to be better than average human driver. That does not imply that they NEVER make mistakes.

I do not know specifics of this case, but a general comment: If somebody is hiding behind a bush, and (deliberately or by mistake) run in front of the car, there is no way the car can anticipate that. There is no way to avoid accidents in 100% of the cases.

We have some corners where old houses are even intruding a bit on the road. When passing these corners you will have to slow down so you can stop in case a child runs out behind the corner. You can't just blame the victim if you are in control of your own speed.

I can think of many situations where I have avoided hitting pedestrians because of my avareness of the situation. Eg: Pedestrian with earphones looking at phone crossing against red light just because the left-turning wehicle in the left lane stopped for a red arrow while I had green going straight. Pedestrian mostly behind the car, just seen thru the window of the car.

Pedestrian behind high snow-walls going towards normal pedestrian crossing, no lights. Almost completely covered by the high snow-walls and a buss parked at a buss station 50 m away from the crossing. 50 km/h road. Since I had seen the pedestrian far away already I knew someone would show up there at the time I arrived there. On the other hand I would never pass a buss like that in high speed, pedestrians like to just run across in front of the buss. And high snow-walls next to a crossing is a big red flag too.

I live in Sweden though, where pedestrians are supposed to be first class citizens that has no armor.

When you are driving you should be prepared to stop. If you're turning into a street you cannot see and you're going faster than you can stop, you're not prepared to stop - you're just hoping that no one is there. This should, and is too in Denmark, fully expected and enforced. This is not the same as as driving along the street and someone is jumping out in front of you.

I have now actually seen the movie of the crash and I can agree that it most likely was hard to avoid for a human. What surprices me is that the LiDAR completely missed her because she didn't run, she didn't jump, she was slowly walking across the road. I can't say if the light was too bad, a camera often looks much darker than what you see with the naked eye, not blinded by other lights. The driver was looking down on the instrument panel at the time of the crash, does he have some view of what the car sees there?

This looks like the exact situation the selfdriving cars are supposed to be able to avoid. A big object in the middle of the street. I expect the car to try to avoid this even though the bike didn't seem to have any reflexes. If the LiDAR doesn't catch this, I don't think they should be out in traffic at all.

> We have some corners where old houses are even intruding a bit on the road. When passing these corners you will have to slow down so you can stop in case a child runs out behind the corner. You can't just blame the victim if you are in control of your own speed.

Yes, but this is a 4-lane roadway. I can totally imagine driving cautiously and slowing down near residential areas where houses are close to the road. However, this seems like a different case.

There are many instances in Asia of people committing suicide by car (jumping in front of a car with no chance for the driver to stop).

Not saying this is the case here, but it could be. As others have said, we need to wait until we know more before jumping to conclusions.

Actually you can't go from 40 miles/ph to 0 miles/ph in an instant. At least not with a passenger car. The reaction time is typically a few seconds. If one throws themselves in front of a car, the car would need a few seconds to react. Based on the speed, distance and other parameters, I don't think any car would be able to stop in an instant.

Thinking about it seriously, it may be shouldn't. Also these things could lead to a crash pile up with other vehicles coming in from behind.

superhUman reaction speed does not mean that the laws of physics stop applying. A vehicule at 40mph will still take the same distance to stop.

It is, actuators still have their lag, probably not much different from foot-pedal combo.

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