Adaptive Cruise and collision avoidance
09-15-2014, 09:04 PM
#1
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Adaptive Cruise and collision avoidance
So I (ab)use the ACC quite a bit. It's a fun tool for all kinds of lazy driving.
Using it in this way I've seen how it reacts in many situations. It's mostly trustworthy, but I have noticed, on more than a few occasions, it not working as expected to a dangerous fault.
The times I can immediately recall have been in the freeway in 30-40MPH traffic when all of a sudden the line of cars in front comes to a very abrupt stop.
Now, of course, as the manual describes, don't put your faith 100% in the ACC and I don't. I'm watching/driving as usual and just letting the ACC do it's thing.
When the abrupt stop occurs, the ACC doesn't react as quickly as I think and I no longer feel safe. In those milliseconds, I respond by moving my foot to the brake. In that short amount of time, I come dangerously close to the vehicle in front and the red collision warning pops up on the dash. I can't test this for sure of course by letting the car handle it and I can't tell for sure if the car is responding in those final milliseconds by applying any brake too, but I can tell you for sure, that I am applying brake.
Anyway, just curious if anyone else is experiencing this. And if anyone has on purpose, or by accident, actually let the car deal with a similar situation and what was the outcome?
I'm almost certain if I didn't apply the brake myself, I would rear-end the vehicles I've been following.
Using it in this way I've seen how it reacts in many situations. It's mostly trustworthy, but I have noticed, on more than a few occasions, it not working as expected to a dangerous fault.
The times I can immediately recall have been in the freeway in 30-40MPH traffic when all of a sudden the line of cars in front comes to a very abrupt stop.
Now, of course, as the manual describes, don't put your faith 100% in the ACC and I don't. I'm watching/driving as usual and just letting the ACC do it's thing.
When the abrupt stop occurs, the ACC doesn't react as quickly as I think and I no longer feel safe. In those milliseconds, I respond by moving my foot to the brake. In that short amount of time, I come dangerously close to the vehicle in front and the red collision warning pops up on the dash. I can't test this for sure of course by letting the car handle it and I can't tell for sure if the car is responding in those final milliseconds by applying any brake too, but I can tell you for sure, that I am applying brake.
Anyway, just curious if anyone else is experiencing this. And if anyone has on purpose, or by accident, actually let the car deal with a similar situation and what was the outcome?
I'm almost certain if I didn't apply the brake myself, I would rear-end the vehicles I've been following.
09-16-2014, 03:31 AM
#2
AudiWorld Super User
I have also seen a few times Braking Guard/Pre-sense showing the warning while ACC is active, mostly on busy highways or interstates. ACC was showing that it noticed the car in front of me but it failed to slow down fast enough so that I took over and braked manually almost at the same time as Braking Guard binged on me. In those situations I would agree with you and say ACC would not have prevented me rear-ending the car in front of me. Braking Guard might have (once it starts braking with full force) but I never tried that or let it happen.
09-16-2014, 03:33 AM
#3
AudiWorld Super User
I use the ACC in a similar fashion to yourself and out of the 14K miles that are on the car, I have been in ACC at least 10K of them so I am a very heavy user.
It is another "assistance" to driving but is not very smart. It doesn't use the data very intelligently and has a hysteresis way to big. I.E. When a car pulls in front, it is too slow to react, if a car brakes then it is also too slow to react, when a car that you are following at a slower speed than what is set moves to another lane then it is too slow to react.
At 2AM, on my drive to work, it is fine because traffic is light and it works as an aid but when in heavier traffic the afore mentioned issues are apparent.
BTW - I used VCDS to default my distance to 2.
The Lane keep assist is of similar value but also operates with a hysteresis of + or - a lane so you cannot trust it either.
These two items will become very common in the next few years and the trickle-down algorithms from driver-less cars will permeate to the masses but, presently, the software is written by 10th graders and the manufacturers get away with bad implementation by calling it an "aid" which means, always keep your foot near the pedal and your hands near the wheel.
It is another "assistance" to driving but is not very smart. It doesn't use the data very intelligently and has a hysteresis way to big. I.E. When a car pulls in front, it is too slow to react, if a car brakes then it is also too slow to react, when a car that you are following at a slower speed than what is set moves to another lane then it is too slow to react.
At 2AM, on my drive to work, it is fine because traffic is light and it works as an aid but when in heavier traffic the afore mentioned issues are apparent.
BTW - I used VCDS to default my distance to 2.
The Lane keep assist is of similar value but also operates with a hysteresis of + or - a lane so you cannot trust it either.
These two items will become very common in the next few years and the trickle-down algorithms from driver-less cars will permeate to the masses but, presently, the software is written by 10th graders and the manufacturers get away with bad implementation by calling it an "aid" which means, always keep your foot near the pedal and your hands near the wheel.
09-16-2014, 05:00 AM
#4
AudiWorld Super User
Selecting ACC "Dynamic" in the Individual setting in the CAR menu helps a bit to mitigate some of this behavior. It accelerates the rate at which the ACC responds to changes in the followed vehicle's speed/distance. On the other hand, the ACC "Comfort" mode is somewhat smoother in responding to the changes while at the same time, can take longer to respond. It seems the engineers tried to make lots of compromises with none of the MMI settings being perfect.
I agree that the ACC/Braking Guard could allow for a more gradual braking as the followed car comes to a complete stop. Short of an sudden emergency stop that would cause a physically impossible situation for the ACC to overcome, it will always brake before allowing a collision. However, at times it can be a bit unnerving and uncomfortable as it brakes later and more forcefully in normal traffic situations than I would use braking manually. Therefore, I occasionally chicken out and hit the brakes before the ACC/Braking Guard engages.
Keep in mind, the ACC cannot recognize any stationary object that it was not previously tracking while in motion. Already stopped vehicles at a light, guard rails, walls, light poles, trees, etc. will be ignored by the ACC or Braking Guard. Also small objects like animals and people are ignored - I'm not sure about motorcycles, scooters or those tiny smart cars.
I agree that the ACC/Braking Guard could allow for a more gradual braking as the followed car comes to a complete stop. Short of an sudden emergency stop that would cause a physically impossible situation for the ACC to overcome, it will always brake before allowing a collision. However, at times it can be a bit unnerving and uncomfortable as it brakes later and more forcefully in normal traffic situations than I would use braking manually. Therefore, I occasionally chicken out and hit the brakes before the ACC/Braking Guard engages.
Keep in mind, the ACC cannot recognize any stationary object that it was not previously tracking while in motion. Already stopped vehicles at a light, guard rails, walls, light poles, trees, etc. will be ignored by the ACC or Braking Guard. Also small objects like animals and people are ignored - I'm not sure about motorcycles, scooters or those tiny smart cars.
09-16-2014, 05:06 AM
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I'll add one piece of info to this: when you "give up" and touch the brake pedal, you disengage ACC, at which point it's all up to you. So a braking guard alert once you've touched the pedal is NOT a call on ACC....
I quickly learned that I had to either trust the ACC or take over braking - there's no in-between of "assisting" it or "just in case"... You're either braking or letting it brake.
I too actually find that ACC seems to slightly under-react during what I consider priority situations, *BUT* I'm not convinced that's objectively true. I think my startle reflex so to speak means I'm more alert and more concerned than the computer is - and it's just going off the numbers. My suspicion is that the "10th graders" are doing things right, in that the car WILL brake in time, but it's not startled like I am. Note that folks complain about braking guard effectively "startling" so even seeing a braking guard warning under ACC *without* driver intervention wouldn't surprise me much.
I quickly learned that I had to either trust the ACC or take over braking - there's no in-between of "assisting" it or "just in case"... You're either braking or letting it brake.
I too actually find that ACC seems to slightly under-react during what I consider priority situations, *BUT* I'm not convinced that's objectively true. I think my startle reflex so to speak means I'm more alert and more concerned than the computer is - and it's just going off the numbers. My suspicion is that the "10th graders" are doing things right, in that the car WILL brake in time, but it's not startled like I am. Note that folks complain about braking guard effectively "startling" so even seeing a braking guard warning under ACC *without* driver intervention wouldn't surprise me much.
09-16-2014, 05:48 AM
#7
AudiWorld Super User
I'm pretty sure that anyone who has used the ACC realizes the system is immediately disengaged when stepping on the brake pedal - no different than any standard cruise control in that respect.
I believe that each person will have their own threshold of comfort re the ACC timing of braking while coming to a stop. I have a friend who always waits until the last possible second before stomping on the brakes at a light, seemingly mere inches from the other car's bumper- I find my right foot constantly pressing down on the passenger footwell carpet every time I ride with him.
I believe that each person will have their own threshold of comfort re the ACC timing of braking while coming to a stop. I have a friend who always waits until the last possible second before stomping on the brakes at a light, seemingly mere inches from the other car's bumper- I find my right foot constantly pressing down on the passenger footwell carpet every time I ride with him.
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09-16-2014, 06:39 AM
#8
AudiWorld Super User
If I am in the middle lane of a 3 lane freeway, using my ACC, in default distance 3, following a car and a car in the inside lane smoothly traverses to the outside lane by dissecting me and my leader then my car will brake too late. By now the traversing car is in the outside lane and my car has just finished compensating for his arrival. Subsequent to my cars determination that the car has now gone from my lane, it will accelerate back up to its pre-determined distance. Meanwhile, I have pissed off the people behind me because my car slowed down and anyone who has more than 3 minutes of driving experience would not have done so because it was an indicated lane change, safe, typical and predictable.
Brake lights are the first indication of deceleration because the light comes on long before deceleration can be determined. If that is the case then why don't they sense the brake lights? Of course, expanding on that theory then you could also add substantial intelligence to the system by recognizing amber turn signals but that will never happen due to the dumb US government agencies that will not mandate amber turn signals, dumb drivers who don't indicate at all, owners who think that reducing the intensity of rear lights by "smoking" them and, again, the 10th graders that write the software.
OK, I'll give up on the 10th graders and start ragging on the lawyers who mandate that stupidity reigns so that they will always have a job. The systems are so lame that they call them "assist" if they actually worked then people would rely on them and the first accident will bring the lawyers back out of the woodwork.
Brake lights are the first indication of deceleration because the light comes on long before deceleration can be determined. If that is the case then why don't they sense the brake lights? Of course, expanding on that theory then you could also add substantial intelligence to the system by recognizing amber turn signals but that will never happen due to the dumb US government agencies that will not mandate amber turn signals, dumb drivers who don't indicate at all, owners who think that reducing the intensity of rear lights by "smoking" them and, again, the 10th graders that write the software.
OK, I'll give up on the 10th graders and start ragging on the lawyers who mandate that stupidity reigns so that they will always have a job. The systems are so lame that they call them "assist" if they actually worked then people would rely on them and the first accident will bring the lawyers back out of the woodwork.
09-16-2014, 07:15 AM
#9
If I am in the middle lane of a 3 lane freeway, using my ACC, in default distance 3, following a car and a car in the inside lane smoothly traverses to the outside lane by dissecting me and my leader then my car will brake too late. By now the traversing car is in the outside lane and my car has just finished compensating for his arrival. Subsequent to my cars determination that the car has now gone from my lane, it will accelerate back up to its pre-determined distance. Meanwhile, I have pissed off the people behind me because my car slowed down and anyone who has more than 3 minutes of driving experience would not have done so because it was an indicated lane change, safe, typical and predictable.
Brake lights are the first indication of deceleration because the light comes on long before deceleration can be determined. If that is the case then why don't they sense the brake lights? Of course, expanding on that theory then you could also add substantial intelligence to the system by recognizing amber turn signals but that will never happen due to the dumb US government agencies that will not mandate amber turn signals, dumb drivers who don't indicate at all, owners who think that reducing the intensity of rear lights by "smoking" them and, again, the 10th graders that write the software.
OK, I'll give up on the 10th graders and start ragging on the lawyers who mandate that stupidity reigns so that they will always have a job. The systems are so lame that they call them "assist" if they actually worked then people would rely on them and the first accident will bring the lawyers back out of the woodwork.
Brake lights are the first indication of deceleration because the light comes on long before deceleration can be determined. If that is the case then why don't they sense the brake lights? Of course, expanding on that theory then you could also add substantial intelligence to the system by recognizing amber turn signals but that will never happen due to the dumb US government agencies that will not mandate amber turn signals, dumb drivers who don't indicate at all, owners who think that reducing the intensity of rear lights by "smoking" them and, again, the 10th graders that write the software.
OK, I'll give up on the 10th graders and start ragging on the lawyers who mandate that stupidity reigns so that they will always have a job. The systems are so lame that they call them "assist" if they actually worked then people would rely on them and the first accident will bring the lawyers back out of the woodwork.
09-16-2014, 07:58 AM
#10
AudiWorld Super User
I don't have this in my Audi, so I may be speaking out of turn, but I think you're wrong to assume it should be perfect and not called assist. Our technology is just not there yet. Jumbo airliners can take off...go over mountain ranges and land all on computers. They don't do it without a pilot at the helm, or hell, a co-pilot for that matter. Those computers are to assist a pilot and nothing more. I'm pretty sure they were designed by people that passed the 11th grade. I would never invest the outcome of my life to any computer system. Furthermore, if they designed them to work by brake lights and turn signals you'd be in deep **** if a bulb blew. lol
Comments:
A plane can fly without a pilot but it cannot without a computer.
You have already entrusted your life to a computer.
The LED bulb that you refer to is one of the most reliable components in the vehicle.
Brake light and indicator recognition may be used as additional intelligence, it should not cause the ejection of your passenger just because a bulb in front of you failed.
Speaking of ejection, if a crash is imminent and the car fails in its endeavor to stop then why would it not eject the passengers in a bubble? This would be a life saving device that could be utilized when infinite G's are about to be spent on your body in a crash of considerable significance. Ok, you may not live but there is no guarantee after you eject from an F18 but if you don't the effect is certain death.