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Discussion Starter · #1 ·
I'm sure someone must know the answer to this. If someone REALLY cuts you off at high speeds (within a few feet of your bumper, for example), what does Adaptive Cruise Control do?

Context: Wondering what will happen in automated vehicles.
 

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Well, the adaptive cruise control will slow your car in order to create distance (as set) between you and the new car that cut you off.

On the other hand, Collision Warning may react and start beeping but it will go away as soon as the car in front of you starts pulling away or your car slows down.
 

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I'm sure different manufacturers probably do different things. We've been cut off in our Durango with ACC, but how our car reacts depends on what the car in front of us is doing. If somebody really cuts us off and they are essentially at the same speed as us or slowing down, our car will brake, "kind of" hard and even start warning us. BUT.. I've also noticed sometimes when other cars have cut us off at basically the same distance BUT they are without a doubt still accelerating away from us, our car seems smart enough that it doesn't do anything or maybe it does a little. It seems like when we are cut off, depending on what speed the object in front is accelerating away from us determines whether maximum allowable braking is applied, no braking is applied, or something in between.

I'd think in a Volvo with CitySafety, if the cut off speed is below that threshold between CitySafety and ACC and depending on what the car in front is doing, that if below, you might have your brakes fully slammed on, and if above, just some threshold of braking is applied.

As for fully automated vehicles years from now, that gets even more complicated. In theory, eventually with all vehicles automated and talking to each other via some inter-car network, I would think you would NOT even be able to cut off the other car? The automated car just wouldn't make that move or the car would ignore your input. The offending car would know the other car is there, and not allow or take that cut off action. Or maybe the cars would somehow "handshake", and the one would slightly slow down and the other would more politely merge in? But then maybe they are also talking with other cars further ahead? I would imagine the world of automated cars is going to be minefield of complex algorithms trying to get cars to drive as politely as possible all together at the same time.

How does one even get from A to B in a fully automated way? Is it going to happen by picking a POI and the car decides what to do and does it while you read the paper? OR, are we going to have semi-automated driving, where we are going to have drive by wire steering too, and the driver is completely isolated from the car, and the car only accepts driver input up to a point. You still point and accelerate and brake, but how much is applied is now 100% up to the car. I actually would kind of love this. I'd bet it would do wonders for fuel efficiency. I've noticed I can get an additional 10-20% better mpg around town even when using ACC between 25-50. I'd love for somebody to tie onboard navigation data speed limits to ACC. Our built in factory garmin GPS knows the road speed limits. It would be really cool if ACC just adjusted it's speed to whatever the nav says the speed limit is. Even better, let me set some threshold I'm willing to go over. Even better, "learn" my habits and what speeds I drive on different roads and then that should even cover roads without data.
 

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I'd think in a Volvo with CitySafety, if the cut off speed is below that threshold between CitySafety and ACC and depending on what the car in front is doing, that if below, you might have your brakes fully slammed on, and if above, just some threshold of braking is applied.
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Not going to happen. City Safety works only if there is no driver input at the time of the conflict. If there is any input from the driver with regards to breaking or steering, City Safery is disabled plus City Safety works in speeds of only up to 30 mph (MY13s) or 19 mph (MY10-MY12s).
 

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Not going to happen. City Safety works only if there is no driver input at the time of the conflict. If there is any input from the driver with regards to breaking or steering, City Safery is disabled plus City Safety works in speeds of only up to 30 mph (MY13s) or 19 mph (MY10-MY12s).
So somebody is driving along at 29mph in a '13 model, they've just taken their foot off the accelerator as they prepare to coast to a stop at a red light, and right then, they are cut off very close by somebody wanting pole position. What happens?

Also, what if somebody is just slightly accelerating from 20-25 and they are cut off, by somebody accelerating faster? I've read the stories of CitySafety activating (and properly actually) as people tried to accelerate from a stop into the back of a car that hadn't actually moved yet. Those were the first CitySafety stories and quite good. Interesting to know it would protect against that. Not something Volvo really advertised.

Also, keep in mind, I said "might". I'm aware CitySafety has features/sensors that auto enable/disable it. But you make it seem like it's impossible for it to go wrong, and we already know, that's not the case. Still, even with the problem reports, CitySafety still gets it right way way way more often than it gets it wrong.
 

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A Wonderland for the computer gigs - embedded software developers...and only cosmos is a limit to the creativity of their curious minds...and since a computer has better reflexes, does not wander around, does not get distracted or tired...once the creativity is unleashed...the algorithms will be more and more sophisticated, and the automated cars - safer and safer...

I am pretty sure that if someone involved in such development somewhere reads our comments, he/she would be screaming to the computer screen - I got it...I got it already covered...
 

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So somebody is driving along at 29mph in a '13 model, they've just taken their foot off the accelerator as they prepare to coast to a stop at a red light, and right then, they are cut off very close by somebody wanting pole position. What happens?
If they drive with foot off the gas pedal and hands off the steering wheel, then it is possible that City Safety could deploy which will not slam the brakes but brake enough to lessen the severity of the impact. That is if the Collision Warning does not activate which could only happen if the car that cut you off also slammed its brakes. If it cut you off but traveled at a speed equal to or great than your car's, nothing would happen.

Also, what if somebody is just slightly accelerating from 20-25 and they are cut off, by somebody accelerating faster?
Nothing would happen.

Also, keep in mind, I said "might". I'm aware CitySafety has features/sensors that auto enable/disable it. But you make it seem like it's impossible for it to go wrong, and we already know, that's not the case. Still, even with the problem reports, CitySafety still gets it right way way way more often than it gets it wrong.
Of course anything could go wrong...nothing is infallible but City Safety (provided that no adverse weather conditions exist and even then it is pretty darn accurate) is a very, very good system and one that is unique in the automotive industry.
 

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On my car, the VARMF comes into play.

(That's the Volvo Automated Raised Middle Finger.)
 

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Also, keep in mind that City Safety only works when the object in front of you is very, very close - much closer than somebody cutting you off at high speeds. That's at least been my experience when it's been triggered by toll gates on the turnpike - the object is literally two-three feet in front of the car.
 

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As for fully automated vehicles years from now, that gets even more complicated. In theory, eventually with all vehicles automated and talking to each other via some inter-car network, I would think you would NOT even be able to cut off the other car? The automated car just wouldn't make that move or the car would ignore your input. The offending car would know the other car is there, and not allow or take that cut off action. Or maybe the cars would somehow "handshake", and the one would slightly slow down and the other would more politely merge in?
Does anyone else find it a sad affair that for a lot of drivings to be polite their control would have to be removed? Btw if there is anyone in Madison area that ever needs work done my best friend has an indy shop and is the only person I trust with my R. He worked as a volvo master tech for 10 years before going independent.


Sent from my SGH-T999 using Tapatalk 2
 

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Are you saying that for '13, Volvo has added steering "grip" sensors to deactivate CitySafety as soon as one puts their hands on the wheel?
No, that is not what I wrote. That is what YOU insinuated that I wrote. City Safety always depended on driver input as to whether it is going to activate or not. When you move the steering wheel to either turn sharply or execute a correction in direction, the car gets input that You are in control. The only time driver input is allowed is if you push the throttle.

Remember, City Safety is designed to take over when you are distracted not when you are actively steering or braking. You can keep your hands on the steering wheel but if you are actively steering then City Safety will not work. Collision Warning, on the other hand, is a different story and uses different technology.
 

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Discussion Starter · #13 ·
Thanks for the answers. And to summarize what Yannis is trying to say, you can still ram people and run over pedestrians if you want to.
 

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In my original comments, I wasn't trying to say anything bad about CitySafety but it seems like you took it that way. All I said was that below that threshold speed, depending on what happens in front of you, CitySafety "might" slam on the brakes. Above that speed, depending on what happens, ACC only brakes to a certain extent, not as much as CitySafety is capable of. From what I've read, CitySafety is capable of FULL braking.

I described scenarios where somebody would be driving straight ahead, their hands on the wheel, but there would be no steering input as far as CitySafety is concerned, as the car is going straight, and the driver is not actively braking, just coasting or keeping pace, so CitySafety would be "on and watching".

I don't want to get into pointless word games with you, but you said "HANDS OFF". YOUR words, not mine. Why did you choose that wording?

Who knows what would really happen if one is cut off extremely close and an object appears suddenly in front by just a few feet if within CitySafety's speed range. With ACC, most likely their car will brake, to a certain extent. With CitySafety? Who knows. And I mean that literally. CitySafety might do nothing. It might do everything. Or something inbetween? Really really depends on what exactly the car in front is doing and just how close it is. Just that if for some reason it does decide to act, irrespective of whether YOU are paying attention or distracted, it's capable of braking way harder than ACC is. My understanding is it has at it's disposal the ability to fully apply the brakes.

I've had my fair share of close calls, and I mean close. I've been cut off at high speeds by a few feet. Of course, at even lower speeds, one is that much more likely to get cut off even closer. Would a CitySafety equipped car activate? I do wonder.... And keep in mind, depending on the scenario, one would WANT IT TO ACTIVATE!!!! Otherwise, next thing you know, we're reading posts titled, "I got cut off in traffic and CitySafety didn't save me!".

The dilemma for these systems is in trying to read the road and other cars the way we do with our minds. For example, that car is slowing down in front of me and turning off the road, but taking their time doing it. I "mostly" know that car will be out of the way when I get there. But how does the system really know that? Is my ACC going to kick in or not? I've read stories of people intentially accelerating so that the system doesn't kick in! I prefer to side with caution, and I get my braking foot ready....

I'm not against CitySafety. I hope someday after it's really been debugged a lot more that it works it's way into more and more cars.
 

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City Safety is a great first effort, IMHO. That said, it is a feature that is going to be used very infrequently, if ever, by most drivers. I have had it for 8 months and it hasn't had a prevent an accident for me yet. I would imagine if City Safety is preventing you from getting into an accident monthly then you either need to change your driving style or take a different route to work!
 

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matt1122,

If we can forget about the stupid word engineering questions and answers, I'll answer the original question -- "I'm sure someone must know the answer to this. If someone REALLY cuts you off at high speeds (within a few feet of your bumper, for example), what does Adaptive Cruise Control do?"

I live in Germany, drive the autobahn every day to work and use ACC almost every day. When you are driving down the left hand lane of the highway at 85-100 mph (135-160 kph over here), Germans don't mind pulling out in front of you suddenly (one blink of the blinkers if you're lucky) when they're going only 60 mph (100 kph) so they can pass a slower moving vehicle (99 kph). It has happened to me on several occations.

1. ACC will automatically apply the brakes -- hard!
2. Collision Warning activates, flashes red lights on the windshield and sounds an alarm.
3. I will usually stomp on the brakes, turning ACC off, and slowing the car.
4. I then apply the middle finger to the idiot that cut me off (below the window/out of sight, because its illegal to show signs of aggression while driving).

I've only had to pull to the left to avoid hitting one person when he entered onto the the autobahn behind a truck and kept on coming into the left lane in front of me without signaling. Forturnately, there was a narrow break-down lane on the left. Generally, there are just steel barriers there.

The S60 is an excellent car for the autobahn. It manuevers well and will keep up with just about anything on the road (I did have problems keeping up with an M6 once).

I hope this helps.
 
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