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Especially on Texas highways where speed limits exceed 80mph, you'd have to be very alert and likely have to swerve over into the next lane (like the other driv

by pants2 3y ago

Especially on Texas highways where speed limits exceed 80mph, you'd have to be very alert and likely have to swerve over into the next lane (like the other driver did). At 80mph, the stopping distance of an average car is around 300 feet once the brake is fully engaged. That exceeds most car radar systems. And with no warning lights the camera won't do much good either.

_dark_matter_ 3y ago
This seems insane, are you telling me that these cars will travel at a speed whose distance is longer than the radar can detect? That is _guaranteeing_ crashes.
- JumpCrisscross 3y ago
  > are you telling me that these cars will travel at a speed whose distance is longer than the radar can detect? "Low beams or dipped lights should shine about 150 to 200 feet ahead, while high beams or brights should shine about 350 to 400 feet ahead" [1]. Would it be customary for someone on that highway to have their high beams engaged? [1] https://autoily.com/how-far-should-headlights-shine/ https://autoily.com/how-far-should-headlights-shine/
  - toast0 3y ago
    High beams are really for rural roads with very little traffic. If there are at least three lanes of traffic in one direction[1] and enough traffic that a car in front was able to see the collision in their rear view mirror, high beams are not advised. Using them in this situation will cause major glare from mirrors of the drivers in front, and possibly for the drivers in the opposing direction. [1] as indicated by the stopped vehicle being reported in the center lane
    - JumpCrisscross 3y ago
      Which makes the radar range being less than the stopping distance less salacious.
      - MBCook 3y ago
        Plus the radar is for gauging relative speed so the car can speed up to the set point if safe or slow down if the car ahead is. It is not for finding stopped stuff in the middle of the road at high speed. I hear there are too many false positives for that to be done.
  - burkaman 3y ago
    I mean yeah if you're on a pitch black highway and you can't see anything outside your headlight beams, you probably shouldn't be going 80 even if that's the speed limit.
    - bongodongobob 3y ago
      No idea where you live but this is probably 99% of highways in the US. Where do you live that the highways are illuminated?
      - burkaman 3y ago
        You can't go 80 on most highways.
      - toast0 3y ago
        No street lights doesn't imply pitch black. It may imply poorly illuminated. I can't find a date, only a time, so I can't guess at lunar illumination or cloud cover. But we don't know how many other vehicles were on the road and what light they were casting. The bystander who reported witnessing the crash was within visual distance, so couldn't have been too far ahead of the MachE. It wasn't reported if there were any other vehicles. If you have enough vehicles on the road (with their lights on) lack of overhead illumination isn't too significant.
      - Free-is-Freedom 3y ago
        Canada
      - progman32 3y ago
        So be it. Going 80+ at night might not be a good idea on most roads.
- pants2 3y ago
  Some vehicles (like my Subaru) offer automatic emergency steering that can save you when there's not enough distance to brake. The Mach-e doesn't have that per my quick Google (they have some assisted thing but it requires manual steering)
  - MBCook 3y ago
    It does not. It has some kind of assist that is supposed to help you swerve fast enough and correct back to normal instead of overcorrecting. It’s designed to fix driver inputs during a panic. You’re right it doesn’t do anything on its own.
user_7832 3y ago
> At 80mph, the stopping distance of an average car is around 300 feet once the brake is fully engaged. That exceeds most car radar systems. And with no warning lights the camera won't do much good either. I think this is a pretty important point for any well-built self-driving software. Does anyone know if radar advancements could help increase this?
- MBCook 3y ago
  My understanding is no. The big problem is that a stopped vehicle looks exactly the same to the radar as any other stationary object. So if it sees something stationary it could be a stopped vehicle or it could be a reflection from a road sign. Or a lip in the pavement. Or something else like that. Basically from what I’ve heard if it were to try and stop whenever it saw something stopped ahead it would constantly slam on the brakes unnecessarily. So stationary things have to be ignored, and it can’t save you from them. They all suffer from this. The only solution I’ve heard of is LIDAR but obviously that’s a huge step up.

by pants2 3y ago

_dark_matter_ 3y ago

This seems insane, are you telling me that these cars will travel at a speed whose distance is longer than the radar can detect? That is _guaranteeing_ crashes.

JumpCrisscross 3y ago
> are you telling me that these cars will travel at a speed whose distance is longer than the radar can detect? "Low beams or dipped lights should shine about 150 to 200 feet ahead, while high beams or brights should shine about 350 to 400 feet ahead" [1]. Would it be customary for someone on that highway to have their high beams engaged? [1] https://autoily.com/how-far-should-headlights-shine/ https://autoily.com/how-far-should-headlights-shine/
- toast0 3y ago
  High beams are really for rural roads with very little traffic. If there are at least three lanes of traffic in one direction[1] and enough traffic that a car in front was able to see the collision in their rear view mirror, high beams are not advised. Using them in this situation will cause major glare from mirrors of the drivers in front, and possibly for the drivers in the opposing direction. [1] as indicated by the stopped vehicle being reported in the center lane
  - JumpCrisscross 3y ago
    Which makes the radar range being less than the stopping distance less salacious.
    - MBCook 3y ago
      Plus the radar is for gauging relative speed so the car can speed up to the set point if safe or slow down if the car ahead is. It is not for finding stopped stuff in the middle of the road at high speed. I hear there are too many false positives for that to be done.
- burkaman 3y ago
  I mean yeah if you're on a pitch black highway and you can't see anything outside your headlight beams, you probably shouldn't be going 80 even if that's the speed limit.
  - bongodongobob 3y ago
    No idea where you live but this is probably 99% of highways in the US. Where do you live that the highways are illuminated?
    - burkaman 3y ago
      You can't go 80 on most highways.
    - toast0 3y ago
      No street lights doesn't imply pitch black. It may imply poorly illuminated. I can't find a date, only a time, so I can't guess at lunar illumination or cloud cover. But we don't know how many other vehicles were on the road and what light they were casting. The bystander who reported witnessing the crash was within visual distance, so couldn't have been too far ahead of the MachE. It wasn't reported if there were any other vehicles. If you have enough vehicles on the road (with their lights on) lack of overhead illumination isn't too significant.
    - Free-is-Freedom 3y ago
      Canada
    - progman32 3y ago
      So be it. Going 80+ at night might not be a good idea on most roads.
pants2 3y ago
Some vehicles (like my Subaru) offer automatic emergency steering that can save you when there's not enough distance to brake. The Mach-e doesn't have that per my quick Google (they have some assisted thing but it requires manual steering)
- MBCook 3y ago
  It does not. It has some kind of assist that is supposed to help you swerve fast enough and correct back to normal instead of overcorrecting. It’s designed to fix driver inputs during a panic. You’re right it doesn’t do anything on its own.

user_7832 3y ago

> At 80mph, the stopping distance of an average car is around 300 feet once the brake is fully engaged. That exceeds most car radar systems. And with no warning lights the camera won't do much good either. I think this is a pretty important point for any well-built self-driving software. Does anyone know if radar advancements could help increase this?

MBCook 3y ago
My understanding is no. The big problem is that a stopped vehicle looks exactly the same to the radar as any other stationary object. So if it sees something stationary it could be a stopped vehicle or it could be a reflection from a road sign. Or a lip in the pavement. Or something else like that. Basically from what I’ve heard if it were to try and stop whenever it saw something stopped ahead it would constantly slam on the brakes unnecessarily. So stationary things have to be ignored, and it can’t save you from them. They all suffer from this. The only solution I’ve heard of is LIDAR but obviously that’s a huge step up.