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> Even normal collision avoidance systems cannot easily detect a semi truck sideways, because semi trucks and trailers in NA aren't required to have side skirts

by usea 3y ago

> Even normal collision avoidance systems cannot easily detect a semi truck sideways, because semi trucks and trailers in NA aren't required to have side skirts and protection bars. This sentence seems to be saying that skirts and protection bars are the reason that self driving cars cannot see these vehicles. Is that really true? Is it a conclusion you've come to on your own, or is it some kind of research or something? It seems like the crux of your whole post, but is absent.

vsskanth 3y ago
So by "normal", I meant the radar-based systems in normal cars, also known as AEB. They are usually mounted low on the front fenders or grille. Semi truck trailers are tall, have a huge empty gap between them and the road, and just high enough to not be seen by the radar. From the radars POV it appears like the road is unobstructed. Obviously this isn't hard to detect with full LIDAR systems in self driving cars because they are on the roof and you have full depth information. This is why I do not mention "self driving cars" in my parent comment.
- aaronbeekay 3y ago
  Do you have a source for this? There’s a gap between semi wheels, sure, but the deck height of a semi trailer in North America is about 48”. If automotive radars weren’t able to detect objects above this height, they would miss a lot of obstacles… One automotive radar I’m familiar with, the Bosch MRR [1], lists a vertical FOV of ±15 degrees, and a 300 m maximum detection range. Assuming the sensor is mounted perpendicular to the ground at 0.5 m high, it should be able to see the top of a 13’6” semi trailer from ~15m away all the way up to its full range. Teslas don’t have radar anyway, so of course this wouldn’t have helped, but an AEB radar that can’t see the top of a semi truck isn’t very useful. [1] https://www.bosch-mobility.com/en/solutions/sensors/front-radar-sensor/ https://www.bosch-mobility.com/en/solutions/sensors/front-ra...
  - vsskanth 3y ago
    Radars are usually tuned to ignore them because they don't have the fidelity to differentiate between a trailer on it's side and a tunnel and it leads to phantom braking.
    - aaronbeekay 3y ago
      Sure, but that’s a lot different from not being able to see them at all.
judge2020 3y ago
While not what you're addressing, yes skirts and underride bars save lives: 2011: https://youtu.be/bT3G-kcKN70 https://youtu.be/bT3G-kcKN70 2013: https://youtu.be/C3MPKLy9qHU https://youtu.be/C3MPKLy9qHU 2018: https://youtu.be/WamlGVhGUYs https://youtu.be/WamlGVhGUYs
- deleted 3y ago
  [deleted]

by usea 3y ago

vsskanth 3y ago

So by "normal", I meant the radar-based systems in normal cars, also known as AEB. They are usually mounted low on the front fenders or grille. Semi truck trailers are tall, have a huge empty gap between them and the road, and just high enough to not be seen by the radar. From the radars POV it appears like the road is unobstructed. Obviously this isn't hard to detect with full LIDAR systems in self driving cars because they are on the roof and you have full depth information. This is why I do not mention "self driving cars" in my parent comment.

aaronbeekay 3y ago
Do you have a source for this? There’s a gap between semi wheels, sure, but the deck height of a semi trailer in North America is about 48”. If automotive radars weren’t able to detect objects above this height, they would miss a lot of obstacles… One automotive radar I’m familiar with, the Bosch MRR [1], lists a vertical FOV of ±15 degrees, and a 300 m maximum detection range. Assuming the sensor is mounted perpendicular to the ground at 0.5 m high, it should be able to see the top of a 13’6” semi trailer from ~15m away all the way up to its full range. Teslas don’t have radar anyway, so of course this wouldn’t have helped, but an AEB radar that can’t see the top of a semi truck isn’t very useful. [1] https://www.bosch-mobility.com/en/solutions/sensors/front-radar-sensor/ https://www.bosch-mobility.com/en/solutions/sensors/front-ra...
- vsskanth 3y ago
  Radars are usually tuned to ignore them because they don't have the fidelity to differentiate between a trailer on it's side and a tunnel and it leads to phantom braking.
  - aaronbeekay 3y ago
    Sure, but that’s a lot different from not being able to see them at all.

judge2020 3y ago

While not what you're addressing, yes skirts and underride bars save lives: 2011: https://youtu.be/bT3G-kcKN70 https://youtu.be/bT3G-kcKN70 2013: https://youtu.be/C3MPKLy9qHU https://youtu.be/C3MPKLy9qHU 2018: https://youtu.be/WamlGVhGUYs https://youtu.be/WamlGVhGUYs

deleted 3y ago
[deleted]