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That actually really sucks to hear, I was hoping that SDVs would adhere and never break the speed limit. 3 MPH at the forces we're talking about can actually ma

That actually really sucks to hear, I was hoping that SDVs would adhere and never break the speed limit. 3 MPH at the forces we're talking about can actually make a difference in life or death.

question_that 9y ago
It would be pretty hilarious if SDVs never broke speed limits, accident after accident caused by irate human drivers attempting to pass.
burntwater 9y ago
I believe it's not clear whether or not it was speeding, From the article, it sounds like it may have been in the middle of transitioning from 35MPH to/from 40MPH.
Mantipath 9y ago
Sure. 3 MPH would have made a difference. So would 3 MPH less after that, and 3MPH more... heck, if it had been going 2 MPH total she'd probably be fine! In the aftermath of a front collision it would always have been safer if the car had been going slightly slower, regardless of the speed limit. The strangest part of watching this story unfold has been discovering that some people have faith that speed limits are anything except a rough guess as to what's mostly safe on a given road. Oh, and subtract 10% from that guess to compensate for the fact that human drivers under 60 years old almost all speed by 4-9 MPH.
- notahacker 9y ago
  According to the UK DOT the estimated pedestrian accident survival rate is 55% at 30mph and just 5% at 40mph (due to kinetic energy rather than reaction times) so 3mph in this range is not exactly an insignificant difference. The strangest thing about watching this story is that people who are apparently ignorant of this still feel sufficiently certain of the relative unimportance of speed differences in this range to sneer at other people for commenting on it. Of course, as others have pointed out, human tendency to ignore speed limits and react badly to vehicles driving slower than ambient traffic speed creates another potential hazard to trade increased accident fatality rates off against when deciding if and when self driving vehicles can speed. It's trolley problems all the way down.
  - lolc 9y ago
    I agree fully with your first paragraph and I chuckled at the "trolley problems all the way down" depiction. However I can't imagine a car company accepting the legal liability of allowing their autonomous cars to go over posted speed limits to "match traffic". In a trolley problem you have the option to refuse a decision. By participating in "speed matching" you become one of the trolleys and you have accepted the unsafe conditions.
    - notahacker 9y ago
      Oh, I'm pretty sure that self driving software isn't being programmed to systematically disregard speed limits to match traffic, not even by a company with Uber's attitude towards regulations, but it is an example of conditions where rigid adherence to speed limits might increase rather than reduce risk.
      - gjm11 9y ago
        With enough self-driving cars on the road (which of course there aren't now), rigid adherence to speed limits might change the safest-and-easiest driving speed for everyone and lead to everyone driving at the limit rather than everyone everyone driving 5mph (or 10mph or whatever) above the limit. So the safest reasonable thing for self-driving cars to do could depend on how many of them there are around. (Of course there are other considerations of that sort. E.g., if all cars on the roads were self-driving then they could coordinate with one another in interesting ways and maybe go substantially faster than human-driven cars for a given level of safety. Maybe not, though, because of risks to pedestrians.)
      - lolc 9y ago
        Hmm, turns out Google cars are programmed to go over speed limits in certain situations. Quote from a Reuters article: Google’s driverless car is programmed to stay within the speed limit, mostly. Research shows that sticking to the speed limit when other cars are going much faster actually can be dangerous, Dolgov says, so its autonomous car can go up to 10 mph (16 kph) above the speed limit when traffic conditions warrant. https://uk.reuters.com/article/us-google-driverless/look-no-hands-test-driving-a-google-car-idUKKBN0GH02P20140817 https://uk.reuters.com/article/us-google-driverless/look-no-... I wonder how they decide over what warrants speeding.
- retsibsi 9y ago
  I see this attitude a lot, but it seems strange to me. Of course any hard line will be somewhat arbitrary, but we need to draw hard lines if we want unambiguous, consistently enforceable laws. What's special about speed limits that makes it okay to ignore them? To me they seem analogous to age-of-consent laws, which of course are not perfectly chosen for every individual -- and of course there's no magical change that occurs on a person's birthday -- but the law reflects society's best judgment of the balance between (protecting the vulnerable and allowing people to make their own choices :: safety and efficiency).
  - Dylan16807 9y ago
    It's analogous to that, except that speed limits very reliably take the reasonable-balance number and then drop it several mph. It's a feedback loop, where people drive faster and limits are set with driving faster in mind.
  - rhacker 9y ago
    I somewhat agree, I keep fighting this on HN - but speed limits are for two categories of people - the people driving, and the people expecting those drivers to be going a specific speed (or range). And 40 - 50 is not a range that is ever safe to put near people. I grew up near (in the bay area) Almaden Expy where the signs post 45 (which means that in the bay area the limit is really 55). Just search for "Almaden Expy killed" in google and let me know if that's a safe street.
- herogreen 9y ago
  You forgot that Ek = 0.5 * m * v² So it is "more dangerous" to be 3 MPH above the speed limit when the speed limit is higher.
cbhl 9y ago
Waymo discovered sections of Mountain View where "the flow of traffic" was routinely 5-10 mph over the speed limit, and driving at the speed limit was actually more dangerous because it caused human drivers to try and go around the vehicle.
- tintor 9y ago
  >> it caused human drivers to try and go around Nope, drivers made that decision on their own. They were not forced into it.
  - kristjansson 9y ago
    Shouldn’t self driving cars be designed to be as safe as possible in the world they’re actually going to drive in, rather than one where everyone else adjusts their behavior?
  - sbov 9y ago
    Luckily caused isn't the same thing as forced, so you are both correct.
  - zamalek 9y ago
    I guess we can call that the trolley paradox.
Sargos 9y ago
Going at or below the speed limit would cause autonomous vehicles to be a hindrance to traffic as real humans know that it's safe to exceed the limit by 5-10 mph. If you hard code the vehicles to arbitrarily go exactly the posted speed then adoption will likely be very difficult and it would actually make the roads a more dangerous place to be as normal traffic would need to veer around the car.

That actually really sucks to hear, I was hoping that SDVs would adhere and never break the speed limit. 3 MPH at the forces we're talking about can actually make a difference in life or death.

question_that 9y ago

It would be pretty hilarious if SDVs never broke speed limits, accident after accident caused by irate human drivers attempting to pass.

burntwater 9y ago

I believe it's not clear whether or not it was speeding, From the article, it sounds like it may have been in the middle of transitioning from 35MPH to/from 40MPH.

Mantipath 9y ago

Sure. 3 MPH would have made a difference. So would 3 MPH less after that, and 3MPH more... heck, if it had been going 2 MPH total she'd probably be fine! In the aftermath of a front collision it would always have been safer if the car had been going slightly slower, regardless of the speed limit. The strangest part of watching this story unfold has been discovering that some people have faith that speed limits are anything except a rough guess as to what's mostly safe on a given road. Oh, and subtract 10% from that guess to compensate for the fact that human drivers under 60 years old almost all speed by 4-9 MPH.

notahacker 9y ago
According to the UK DOT the estimated pedestrian accident survival rate is 55% at 30mph and just 5% at 40mph (due to kinetic energy rather than reaction times) so 3mph in this range is not exactly an insignificant difference. The strangest thing about watching this story is that people who are apparently ignorant of this still feel sufficiently certain of the relative unimportance of speed differences in this range to sneer at other people for commenting on it. Of course, as others have pointed out, human tendency to ignore speed limits and react badly to vehicles driving slower than ambient traffic speed creates another potential hazard to trade increased accident fatality rates off against when deciding if and when self driving vehicles can speed. It's trolley problems all the way down.
- lolc 9y ago
  I agree fully with your first paragraph and I chuckled at the "trolley problems all the way down" depiction. However I can't imagine a car company accepting the legal liability of allowing their autonomous cars to go over posted speed limits to "match traffic". In a trolley problem you have the option to refuse a decision. By participating in "speed matching" you become one of the trolleys and you have accepted the unsafe conditions.
  - notahacker 9y ago
    Oh, I'm pretty sure that self driving software isn't being programmed to systematically disregard speed limits to match traffic, not even by a company with Uber's attitude towards regulations, but it is an example of conditions where rigid adherence to speed limits might increase rather than reduce risk.
    - gjm11 9y ago
      With enough self-driving cars on the road (which of course there aren't now), rigid adherence to speed limits might change the safest-and-easiest driving speed for everyone and lead to everyone driving at the limit rather than everyone everyone driving 5mph (or 10mph or whatever) above the limit. So the safest reasonable thing for self-driving cars to do could depend on how many of them there are around. (Of course there are other considerations of that sort. E.g., if all cars on the roads were self-driving then they could coordinate with one another in interesting ways and maybe go substantially faster than human-driven cars for a given level of safety. Maybe not, though, because of risks to pedestrians.)
    - lolc 9y ago
      Hmm, turns out Google cars are programmed to go over speed limits in certain situations. Quote from a Reuters article: Google’s driverless car is programmed to stay within the speed limit, mostly. Research shows that sticking to the speed limit when other cars are going much faster actually can be dangerous, Dolgov says, so its autonomous car can go up to 10 mph (16 kph) above the speed limit when traffic conditions warrant. https://uk.reuters.com/article/us-google-driverless/look-no-hands-test-driving-a-google-car-idUKKBN0GH02P20140817 https://uk.reuters.com/article/us-google-driverless/look-no-... I wonder how they decide over what warrants speeding.
retsibsi 9y ago
I see this attitude a lot, but it seems strange to me. Of course any hard line will be somewhat arbitrary, but we need to draw hard lines if we want unambiguous, consistently enforceable laws. What's special about speed limits that makes it okay to ignore them? To me they seem analogous to age-of-consent laws, which of course are not perfectly chosen for every individual -- and of course there's no magical change that occurs on a person's birthday -- but the law reflects society's best judgment of the balance between (protecting the vulnerable and allowing people to make their own choices :: safety and efficiency).
- Dylan16807 9y ago
  It's analogous to that, except that speed limits very reliably take the reasonable-balance number and then drop it several mph. It's a feedback loop, where people drive faster and limits are set with driving faster in mind.
- rhacker 9y ago
  I somewhat agree, I keep fighting this on HN - but speed limits are for two categories of people - the people driving, and the people expecting those drivers to be going a specific speed (or range). And 40 - 50 is not a range that is ever safe to put near people. I grew up near (in the bay area) Almaden Expy where the signs post 45 (which means that in the bay area the limit is really 55). Just search for "Almaden Expy killed" in google and let me know if that's a safe street.
herogreen 9y ago
You forgot that Ek = 0.5 * m * v² So it is "more dangerous" to be 3 MPH above the speed limit when the speed limit is higher.

cbhl 9y ago

Waymo discovered sections of Mountain View where "the flow of traffic" was routinely 5-10 mph over the speed limit, and driving at the speed limit was actually more dangerous because it caused human drivers to try and go around the vehicle.

tintor 9y ago
>> it caused human drivers to try and go around Nope, drivers made that decision on their own. They were not forced into it.
- kristjansson 9y ago
  Shouldn’t self driving cars be designed to be as safe as possible in the world they’re actually going to drive in, rather than one where everyone else adjusts their behavior?
- sbov 9y ago
  Luckily caused isn't the same thing as forced, so you are both correct.
- zamalek 9y ago
  I guess we can call that the trolley paradox.

Sargos 9y ago

Going at or below the speed limit would cause autonomous vehicles to be a hindrance to traffic as real humans know that it's safe to exceed the limit by 5-10 mph. If you hard code the vehicles to arbitrarily go exactly the posted speed then adoption will likely be very difficult and it would actually make the roads a more dangerous place to be as normal traffic would need to veer around the car.