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Self driving cars are still subject to the laws of physics... unless you're going to dictate that self-driving cars never go above 15mph, I wouldn't advocate ju

Self driving cars are still subject to the laws of physics... unless you're going to dictate that self-driving cars never go above 15mph, I wouldn't advocate jumping in front of even a "perfect" self-driving car. Braking distance (without including any decision time) for a 15mph car is 11 ft, for a 30mph is 45 ft. Self driving cars won't change these limits. (well, they may be a little better than humans at maximizing braking power through threshold braking on all 4 wheels, but it won't be dramatically different) So even with perfect reaction times, it will still be possible for a self-driving car to hit a human who enters its path unexpectedly.

pishpash 9y ago
Then we should at least learn their capabilities by throwing jumping dummies at them. Call it the new dummy testing. It's the least we can do. Did Travis bro do this when he set the plan in motion?
- yjftsjthsd-h 9y ago
  We don't throw jumping dummies in front of human students before we let them drive; why should machines be different?
  - jjeaff 9y ago
    Because it's assumed human drivers will at least have a desire to stop. If a machine isn't properly programmed, it will plow right through a crowd and never look back.
  - adrianN 9y ago
    Because we have a pretty good idea of how humans react in traffic, but we're still a bit unsure about robots.
  - rlkf 9y ago
    Maybe not in the U.S., but in Norway, as part of getting the driver's license, you'll have to take an ice driving course, where, amongst other things, a dummy is swung at your car while driving on an oiled lane in 30 mph. (It is practically impossible to steer away from the dummy, which is the meaning of the exercise; to realize the folly of driving too fast on icy roads)
  - pishpash 9y ago
    There is no inherent equality between humans and machines. Is it conceptually difficult to grasp that machines can be held to a different standard?
bobthepanda 9y ago
Indeed. This is why many cities are reducing speed limits. In fact, self-driving cars may actually improve the situation if cars actually start complying with speed limits en masse.
- Johnny555 9y ago
  Good point -- there's a 4% chance of fatality when struck by a 15mph car versus 20% at 30mph. There's a 30mph city street near me where cars routinely go 45mph -- the fatality rate jumps up to 60% at that speed. So just having cars follow the speed limit would go a long way toward reducing fatalities. https://www.propublica.org/article/unsafe-at-many-speeds https://www.propublica.org/article/unsafe-at-many-speeds
- mhb 9y ago
  Indeed what? It's obvious that slower cars will kill fewer people. That's meaningless without saying what the cost of driving slower is.
  - jessaustin 9y ago
    You'll have to leave earlier for your important appointment!
    - mhb 9y ago
      I suppose you're suggesting there's a distinction between someone losing x hours of life due to travel time vs. someone being killed and losing y hours of life. I'm sure you can see why someone attempting to create a reasonable policy might avoid making that distinction.
      - jessaustin 9y ago
        I thought you were asking about "the cost of driving slower"? I'm perfectly serious in my answer. Any transportation goal (with the possible exception of ambulance service?) that may be accomplished at high speed, also can be accomplished at lower speed, with sufficient planning.
astrodust 9y ago
Unlike humans who have limited vision, self-driving cars are generally able to observe all obstacles in all directions and compute, in real-time, the probability of a collision. If a car can't observe any potential hazards that might impact it using different threat models it should drive more slowly. Blowing down a narrow street with parked cars on both sides at precisely the speed limit is not a good plan.
- mr_toad 9y ago
  You could do that, but how far do you take it? Do you program a car to slow to 10mph every time it passes a parked delivery van just in case? Would people find that acceptable?
  - nugi 9y ago
    Yes? If self driving is being hailed as being safer, it, you know, should be. If that means doing all the boring stuff I would not bother to, so be it. How else will they be safer unless by ignoring our driving biases?
francisofascii 9y ago
The speed limit for this particular stretch was 45 mph. (sounds high to me, considering there is a bike lane)
- rrix2 9y ago
  Phoenix transportation infrastructure is notoriously bad at handling pedestrians and bicycles because so few people are going to be out biking in 120F summers. There's a knock off effect of exclusively designing a city around middle class car and house types of folks. It's why I left after 20 years in Phoenix and Tempe.
- smileysteve 9y ago
  In Atlanta, bicycles are cars share the road (with or without a bike lane) at 45mph speed limits.
ubernostrum 9y ago
Once upon a time when I was learning to drive, one of the exercises my instructor used was to put me in the passenger seat while he drove, and have me try to point out every person or vehicle capable of entering the lane he was driving in, as soon as I became aware of them. Every parked vehicle along the side of a road. Every vehicle approaching or waiting to enter an intersection. Every pedestrian standing by a crosswalk or even walking along the sidewalk adjacent to the traffic lane. Every bicycle. Every vehicle traveling the opposite direction on streets without a hard median. And every time I missed one, he would point and say "what about that car over there?" or "what about that person on the sidewalk?" He made me do this until I didn't miss any. And then he started me on watching for suspicious gaps in the parked cards along the side that could indicate a loading bay or a driveway or an alley or a hidden intersection. And so on though multiple categories of collision hazards, and then verbally indicating them to him while I was driving. And the reason for that exercise was to drive home the point that if there's a vehicle or a person that could get into my lane, it's my job as a defensive driver to be aware of that and be ready to react. Which includes making sure I could stop or avoid in time if I needed to. I don't know how driving is taught now, but I would hope a self-driving system could at the very least match what my human driving instructor was capable of.
- J_Sherz 9y ago
  Sounds like you had a great driving instructor. Although I never had an experience like that when learning to drive, we did have to complete something in the UK called a "hazard perception test"[1] in order to get a drivers license. Basically a video version of what your instructor did for you. Until reading your comment today, I'd never really put much thought into how useful this is and how ingrained in my everyday driving it is. [1] https://www.youtube.com/watch?v=SdQRkmdhwJs https://www.youtube.com/watch?v=SdQRkmdhwJs
  - ubernostrum 9y ago
    A thing I like to do to stay in practice is to browse /r/roadcam over on reddit. I open a video at random and watch it, and try to guess where the collision (or near-collision) is going to come from.
rout39574 9y ago
So, there's a performance envelope expected. Sure, someone can bungee jump off an overpass and not be avoidable. :) But they should be willing to walk in front of it in an in-spec performance regime. There's some really good Volvo commercials along that line, with engineers standing in front of a truck.
Spare_account 9y ago
Braking distance ... for a 30mph is 45 ft Apologies for going off topic here, but I'm curious about this. I've tested every car I've ever owned and all of the recent cars with all-round disc brakes have outperformed this statistic, but I've never been able to get agreement from other people (unless I demonstrate it to them in person). I'm talking about optimal conditions here, wet roads would change things obviously but each of these cars was able to stop within it's own car length (around 15 feet) from 30mph, simply by stamping on the brake pedal with maximum force, triggering the ABS until the car stops: 2001 Nissan Primera SE 2003 BMW 325i Touring (E46) 2007 Peugeot 307 1.6 S 2011 Ford S-Max I can't work out how any modern car, even in the wet, could need 45 feet to stop. In case it's not obvious, this is only considering mechanical stopping distance, human reaction time (or indeed computer reaction time which is the main topic here) would extend this distance, but the usual 45 feet from 30mph statistic doesn't include reaction time either.
- jaxbot 9y ago
  In addition, some cars such as the Nissan Leaf have a feature that locks the brakes at full power when there is a sudden control shift from accelerator to brakes, meaning that if you stomp on the brakes and then reduce pressure, the car will continue to brake at maximum power. This was done for two reasons: one, people hesitating in emergency situations, and two, people being taught to pump brakes, which increases braking distance in cars with ABS. I learned about this feature when reading car forums for my car and finding threads from people who were rear-ended when they accidentally triggered this feature by slamming on the brakes when they didn't intend to come to a complete stop.
  - 0xffff2 9y ago
    That seems deeply unexpected. Was there any resolution or response from Nissan in any of the cases you read about?
  - alacombe 9y ago
    > In addition, some cars such as the Nissan Leaf have a feature that locks the brakes at full power when there is a sudden control shift from accelerator to brakes, meaning that if you stomp on the brakes and then reduce pressure, the car will continue to brake at maximum power. Which is utterly stupid. Braking is the natural reflex, but not always the right one. I've been in more than one close call (think left turn on incoming traffic) where the correct response was not to floor the brake, but floor the gas. > people being taught to pump brakes, which increases braking distance in cars with ABS. Which is a mechanical turk version of what the ABS is doing under the hood.
dlwdlw 9y ago
If self driving cars are limited to speeds that allow them to stop within their lidar max range is that too slow? Humans don't have the pinpoint accuracy of lidar but our visual algorithms are very flexible and robust and also have very strong confidence signals e.g driving more carefully in dark rain. Cameras are not accurate enough though, their dynamic range being terrible. Wonder how humans would fare if forced to wear goggles that approximated a lidar sensors information.
PantaloonFlames 9y ago
The advantage self-drivers have is in 1. minimizing distraction / optimizing perception 2. minimizing reaction time. Theoretically self-drivers will always see everything that is relevant, unlike a human driver. And theoretically a robot-driver will always react more quickly than even a hyper-attentive human driver, who has to move meat in order to apply the brake.
emodendroket 9y ago
But is that the actual situation we're talking about? Or are we actually talking about a situation where the person may have been jaywalking but would have had a reasonable expectation that a human driver would stop? I walk a decent distance to work every day and I don't think anyone totally adheres to the lights and crosswalks (not least because if you do you will be running into the road just as everyone races to make a right turn into the same crosswalk you're in).
gkya 9y ago
What about steering away, a la ABS?

pishpash 9y ago

Then we should at least learn their capabilities by throwing jumping dummies at them. Call it the new dummy testing. It's the least we can do. Did Travis bro do this when he set the plan in motion?

yjftsjthsd-h 9y ago
We don't throw jumping dummies in front of human students before we let them drive; why should machines be different?
- jjeaff 9y ago
  Because it's assumed human drivers will at least have a desire to stop. If a machine isn't properly programmed, it will plow right through a crowd and never look back.
- adrianN 9y ago
  Because we have a pretty good idea of how humans react in traffic, but we're still a bit unsure about robots.
- rlkf 9y ago
  Maybe not in the U.S., but in Norway, as part of getting the driver's license, you'll have to take an ice driving course, where, amongst other things, a dummy is swung at your car while driving on an oiled lane in 30 mph. (It is practically impossible to steer away from the dummy, which is the meaning of the exercise; to realize the folly of driving too fast on icy roads)
- pishpash 9y ago
  There is no inherent equality between humans and machines. Is it conceptually difficult to grasp that machines can be held to a different standard?

bobthepanda 9y ago

Indeed. This is why many cities are reducing speed limits. In fact, self-driving cars may actually improve the situation if cars actually start complying with speed limits en masse.

Johnny555 9y ago
Good point -- there's a 4% chance of fatality when struck by a 15mph car versus 20% at 30mph. There's a 30mph city street near me where cars routinely go 45mph -- the fatality rate jumps up to 60% at that speed. So just having cars follow the speed limit would go a long way toward reducing fatalities. https://www.propublica.org/article/unsafe-at-many-speeds https://www.propublica.org/article/unsafe-at-many-speeds
mhb 9y ago
Indeed what? It's obvious that slower cars will kill fewer people. That's meaningless without saying what the cost of driving slower is.
- jessaustin 9y ago
  You'll have to leave earlier for your important appointment!
  - mhb 9y ago
    I suppose you're suggesting there's a distinction between someone losing x hours of life due to travel time vs. someone being killed and losing y hours of life. I'm sure you can see why someone attempting to create a reasonable policy might avoid making that distinction.
    - jessaustin 9y ago
      I thought you were asking about "the cost of driving slower"? I'm perfectly serious in my answer. Any transportation goal (with the possible exception of ambulance service?) that may be accomplished at high speed, also can be accomplished at lower speed, with sufficient planning.

astrodust 9y ago

Unlike humans who have limited vision, self-driving cars are generally able to observe all obstacles in all directions and compute, in real-time, the probability of a collision. If a car can't observe any potential hazards that might impact it using different threat models it should drive more slowly. Blowing down a narrow street with parked cars on both sides at precisely the speed limit is not a good plan.

mr_toad 9y ago
You could do that, but how far do you take it? Do you program a car to slow to 10mph every time it passes a parked delivery van just in case? Would people find that acceptable?
- nugi 9y ago
  Yes? If self driving is being hailed as being safer, it, you know, should be. If that means doing all the boring stuff I would not bother to, so be it. How else will they be safer unless by ignoring our driving biases?

francisofascii 9y ago

The speed limit for this particular stretch was 45 mph. (sounds high to me, considering there is a bike lane)

rrix2 9y ago
Phoenix transportation infrastructure is notoriously bad at handling pedestrians and bicycles because so few people are going to be out biking in 120F summers. There's a knock off effect of exclusively designing a city around middle class car and house types of folks. It's why I left after 20 years in Phoenix and Tempe.
smileysteve 9y ago
In Atlanta, bicycles are cars share the road (with or without a bike lane) at 45mph speed limits.

ubernostrum 9y ago

Once upon a time when I was learning to drive, one of the exercises my instructor used was to put me in the passenger seat while he drove, and have me try to point out every person or vehicle capable of entering the lane he was driving in, as soon as I became aware of them. Every parked vehicle along the side of a road. Every vehicle approaching or waiting to enter an intersection. Every pedestrian standing by a crosswalk or even walking along the sidewalk adjacent to the traffic lane. Every bicycle. Every vehicle traveling the opposite direction on streets without a hard median. And every time I missed one, he would point and say "what about that car over there?" or "what about that person on the sidewalk?" He made me do this until I didn't miss any. And then he started me on watching for suspicious gaps in the parked cards along the side that could indicate a loading bay or a driveway or an alley or a hidden intersection. And so on though multiple categories of collision hazards, and then verbally indicating them to him while I was driving. And the reason for that exercise was to drive home the point that if there's a vehicle or a person that could get into my lane, it's my job as a defensive driver to be aware of that and be ready to react. Which includes making sure I could stop or avoid in time if I needed to. I don't know how driving is taught now, but I would hope a self-driving system could at the very least match what my human driving instructor was capable of.

J_Sherz 9y ago
Sounds like you had a great driving instructor. Although I never had an experience like that when learning to drive, we did have to complete something in the UK called a "hazard perception test"[1] in order to get a drivers license. Basically a video version of what your instructor did for you. Until reading your comment today, I'd never really put much thought into how useful this is and how ingrained in my everyday driving it is. [1] https://www.youtube.com/watch?v=SdQRkmdhwJs https://www.youtube.com/watch?v=SdQRkmdhwJs
- ubernostrum 9y ago
  A thing I like to do to stay in practice is to browse /r/roadcam over on reddit. I open a video at random and watch it, and try to guess where the collision (or near-collision) is going to come from.

rout39574 9y ago

So, there's a performance envelope expected. Sure, someone can bungee jump off an overpass and not be avoidable. :) But they should be willing to walk in front of it in an in-spec performance regime. There's some really good Volvo commercials along that line, with engineers standing in front of a truck.

Spare_account 9y ago

Braking distance ... for a 30mph is 45 ft Apologies for going off topic here, but I'm curious about this. I've tested every car I've ever owned and all of the recent cars with all-round disc brakes have outperformed this statistic, but I've never been able to get agreement from other people (unless I demonstrate it to them in person). I'm talking about optimal conditions here, wet roads would change things obviously but each of these cars was able to stop within it's own car length (around 15 feet) from 30mph, simply by stamping on the brake pedal with maximum force, triggering the ABS until the car stops: 2001 Nissan Primera SE 2003 BMW 325i Touring (E46) 2007 Peugeot 307 1.6 S 2011 Ford S-Max I can't work out how any modern car, even in the wet, could need 45 feet to stop. In case it's not obvious, this is only considering mechanical stopping distance, human reaction time (or indeed computer reaction time which is the main topic here) would extend this distance, but the usual 45 feet from 30mph statistic doesn't include reaction time either.

jaxbot 9y ago
In addition, some cars such as the Nissan Leaf have a feature that locks the brakes at full power when there is a sudden control shift from accelerator to brakes, meaning that if you stomp on the brakes and then reduce pressure, the car will continue to brake at maximum power. This was done for two reasons: one, people hesitating in emergency situations, and two, people being taught to pump brakes, which increases braking distance in cars with ABS. I learned about this feature when reading car forums for my car and finding threads from people who were rear-ended when they accidentally triggered this feature by slamming on the brakes when they didn't intend to come to a complete stop.
- 0xffff2 9y ago
  That seems deeply unexpected. Was there any resolution or response from Nissan in any of the cases you read about?
- alacombe 9y ago
  > In addition, some cars such as the Nissan Leaf have a feature that locks the brakes at full power when there is a sudden control shift from accelerator to brakes, meaning that if you stomp on the brakes and then reduce pressure, the car will continue to brake at maximum power. Which is utterly stupid. Braking is the natural reflex, but not always the right one. I've been in more than one close call (think left turn on incoming traffic) where the correct response was not to floor the brake, but floor the gas. > people being taught to pump brakes, which increases braking distance in cars with ABS. Which is a mechanical turk version of what the ABS is doing under the hood.

dlwdlw 9y ago

If self driving cars are limited to speeds that allow them to stop within their lidar max range is that too slow? Humans don't have the pinpoint accuracy of lidar but our visual algorithms are very flexible and robust and also have very strong confidence signals e.g driving more carefully in dark rain. Cameras are not accurate enough though, their dynamic range being terrible. Wonder how humans would fare if forced to wear goggles that approximated a lidar sensors information.

PantaloonFlames 9y ago

The advantage self-drivers have is in 1. minimizing distraction / optimizing perception 2. minimizing reaction time. Theoretically self-drivers will always see everything that is relevant, unlike a human driver. And theoretically a robot-driver will always react more quickly than even a hyper-attentive human driver, who has to move meat in order to apply the brake.

emodendroket 9y ago

But is that the actual situation we're talking about? Or are we actually talking about a situation where the person may have been jaywalking but would have had a reasonable expectation that a human driver would stop? I walk a decent distance to work every day and I don't think anyone totally adheres to the lights and crosswalks (not least because if you do you will be running into the road just as everyone races to make a right turn into the same crosswalk you're in).

gkya 9y ago

What about steering away, a la ABS?