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What theory is this? Unless the vehicle is moving at such a rate of speed as to not be in the RADAR scope for longer than the PRF (pulse-repetition frequency) of the system, the vehicle can be detected.

With a PRF of 300pps (pretty low) and a vehicle length of 18ft, the car would need a speed delta north of 3500mph to not be seen by the RADAR.
these are low quality radar and they are heavily filtering them to not have false positives from every stationary object on the side of the road

So the only things seen by the radar are things that are going a similar speed as you.

That's why the forward facing radar in nearly every ADAS system on the road will not respond to a vehicle going more than 30mph slower than you

When you come from comma.ai or tesla systems you forget that other ADAS systems do not react to slow moving or stationary vehicles
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these are low quality radar and they are heavily filtering them to not have false positives from every stationary object on the side of the road

So the only things seen by the radar are things that are going a similar speed as you.

That's why the forward facing radar in nearly every ADAS system on the road will not respond to a vehicle going more than 30mph slower than you

When you come from comma.ai or tesla systems you forget that other ADAS systems do not react to slow moving or stationary vehicles
This does not match my experience. 2006 Toyota Sienna with dynamic RADAR cruise control would "see" and react to slower traffic. My R1T will ABSOLUTELY see, warn, and react to slow traffic as well, for better or worse (it slows prematurely for stopped or turning traffic, and is slow to resume speed).
 

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This does not match my experience. 2006 Toyota Sienna with dynamic RADAR cruise control would "see" and react to slower traffic. My R1T will ABSOLUTELY see, warn, and react to slow traffic as well, for better or worse (it slows prematurely for stopped or turning traffic, and is slow to resume speed).
It actually does not. You think it does because it slows down for a lead car which brings you into the slow moving traffic.

I drove a 2021 toyota corolla with radar cruise a couple months ago and I know it does not see stopped traffic, but it was only once in a 500 mile drive that I encountered a traffic scenario where the car truly could not see it. Most of the time I had a lead car assist the car in slowing down.

You can actually see in car ADAS systems this scenario:

you have a slow moving car ahead which leads you into stopped traffic. Then the slow moving car decides to merge right/left to pass the stopped car ahead.

now your ADAS car (lets assume going faster than 30mph) thinks the lane has become empty again and will ACCELERATE into stopped traffic to return to the set speed.


This is a fundamental limitation of how radar works. The way to get around this problem is to use vision exactly like comma.ai and tesla are doing. You can detect objects simply from video feeds and using depth estimation.

Ford's bluecruise system is under investigation by the NHTSA because the car ran into a stationary vehicle at night. However when they investigate the system they will find it will hit those same cars in broad daylight at much slower speeds. This might cause a recall
 

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It actually does not. You think it does because it slows down for a lead car which brings you into the slow moving traffic.

I drove a 2021 toyota corolla with radar cruise a couple months ago and I know it does not see stopped traffic, but it was only once in a 500 mile drive that I encountered a traffic scenario where the car truly could not see it. Most of the time I had a lead car assist the car in slowing down.
I suppose you're right. My nearly 20 years of driving the vehicle is no match for your 500 miles. My bad.
This is a fundamental limitation of how radar works. The way to get around this problem is to use vision exactly like comma.ai and tesla are doing. You can detect objects simply from video feeds and using depth estimation.
What fundamental limitation are you talking about? I've used RADAR systems for two decades and have never encountered this 'fundamental limitation'.
 

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I suppose you're right. My nearly 20 years of driving the vehicle is no match for your 500 miles. My bad.

What fundamental limitation are you talking about? I've used RADAR systems for two decades and have never encountered this 'fundamental limitation'.
This is a limitation because the radar that is used in vehicles is a very low resolution radar with almost no vertical resolution. This radar cannot distinguish between a stopped car, a highway overpass, or something on the side of the road.

There are many other limitations.

"Traffic-Aware Cruise Control cannot detect all objects and may not brake/decelerate for stationary vehicles, especially in situations when you are driving over 50 mph (80 km/h) and a vehicle you are following moves out of your driving path and a stationary vehicle or object is in front of you instead."

This is straight from the tesla manual with autopilot from 2015. A situation which I exactly described. Your car will ACCELERATE into stationary traffic.


With Ford bluecruise it seems to not see a stationary vehicle at above 30mph but below 40mph emergency braking or some kind of late braking will save the car. At above 40mph I don't want to know what will happen.

Because I never use any driver assist other than comma.ai or tesla FSD, I get spooked when I go into another car and forget about this limitation, because it doesn't happen unless the right circumstances are met. Usually there is a lead car
 

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This is a limitation because the radar that is used in vehicles is a very low resolution radar with almost no vertical resolution. This radar cannot distinguish between a stopped car, a highway overpass, or something on the side of the road.

There are many other limitations.

"Traffic-Aware Cruise Control cannot detect all objects and may not brake/decelerate for stationary vehicles, especially in situations when you are driving over 50 mph (80 km/h) and a vehicle you are following moves out of your driving path and a stationary vehicle or object is in front of you instead."

This is straight from the tesla manual with autopilot from 2015. A situation which I exactly described. Your car will ACCELERATE into stationary traffic.


With Ford bluecruise it seems to not see a stationary vehicle at above 30mph but below 40mph emergency braking or some kind of late braking will save the car. At above 40mph I don't want to know what will happen.

Because I never use any driver assist other than comma.ai or tesla FSD, I get spooked when I go into another car and forget about this limitation, because it doesn't happen unless the right circumstances are met. Usually there is a lead car
The situation you described to me was applicable to non-Tesla vehicles...
When you come from comma.ai or tesla systems you forget that other ADAS systems do not react to slow moving or stationary vehicles
but the above quote was from a Tesla manual...
 
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I setup my Comma 3x today in advance of receiving my harness. For those of you who are getting a new Comma device, I had to install the stock OpenPilot first, then factory reset the device, and only then would the custom branch for Rivian work. FYI. Feel free to PM me if anyone needs setup help. I'll be making an installation video as well once I get my harness.
 

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The situation you described to me was applicable to non-Tesla vehicles...

but the above quote was from a Tesla manual...
read whatever vehicle manual you want. They all have this limitation. Straight from the toyota manual

Rivian R1T R1S Comma AI/OpenPilot Update -- Watch it in Action on Gen1 Rivian (Video) 1738805114061-kl
 

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here's a video from a mustang mach-e. Look you can see in the simplest possible scenario that the car does not even react to a stationary vehicle. As if it is completely invisible

 

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read whatever vehicle manual you want. They all have this limitation. Straight from the toyota manual

1738805114061-kl.jpg
Neat, it does say 'may not' not 'will not'.

But how does this apply to our original topic, the blind spot monitoring system?
 

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Neat, it does say 'may not' not 'will not'.

But how does this apply to our original topic, the blind spot monitoring system?
because it is a limitation of radar and how it is used.

And by the way, the "may not" is a "will not" but the only reason it says "may not" is because at around 35mph or less your car will react to a stationary vehicle.

So my point is a car going about 35mph or greater difference from the speed that you are moving and you will have problems

I believe in the mercedes manual they specifically state a speed at which this limitation exists
 

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because it is a limitation of radar and how it is used.

And by the way, the "may not" is a "will not" but the only reason it says "may not" is because at around 35mph or less your car will react to a stationary vehicle.

So my point is a car going about 35mph or greater difference from the speed that you are moving and you will have problems

I believe in the mercedes manual they specifically state a speed at which this limitation exists
Yeah, there's no way this applies to blind spot systems.
 

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Yeah, there's no way this applies to blind spot systems.
yes it does because it's based on radar.

If you are caught behind a slow vehicle going 30 while the passing lane is going 65, you'll have the same problem.

You can go to other forums by doing a google search and seeing evidence of this. BMW is one I found.

Tesla is the unique exception in that their blind spot system is entirely based on cameras
 

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yes it does because it's based on radar.

If you are caught behind a slow vehicle going 30 while the passing lane is going 65, you'll have the same problem.

You can go to other forums by doing a google search and seeing evidence of this. BMW is one I found.

Tesla is the unique exception in that their blind spot system is entirely based on cameras
Collision avoidance systems use RADAR as well... If your stated restrictions applied to all Radar systems, how would any of them work without simply smashing into every stopped car in front of them?
 

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Collision avoidance systems use RADAR as well... If your stated restrictions applied to all Radar systems, how would any of them work without simply smashing into every stopped car in front of them?
they use a combination of radar and cameras and are tuned for last minute braking. They don't work very well.

Collision avoidance systems (i.e auto emergency braking) will not prevent an accident but slow you down to reduce injury


only will they prevent a collision completely at a low speed (i.e. 30mph)


That's why what tesla is doing is wholly unique. By tracking every single thing around you (stationary or otherwise) you can predict the trajectory of how it is moving and whether it will hit you or not.

That's why nobody else for 10 years will probably have a collision avoidance system which can react to traffic that moving perpendicular to you, i.e. a deer, child, animmal etc. runs across the road. Car runs a red light, etc.
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