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Oof, my experience with with auto-brake in a 2021 Subaru Crosstrek (anecdotal, sample size of one, all that good stuff) is much the opposite. It's too sensitive

by branon 4y ago

Oof, my experience with with auto-brake in a 2021 Subaru Crosstrek (anecdotal, sample size of one, all that good stuff) is much the opposite. It's too sensitive and tends to brake shockingly hard during fairly mundane maneuvers. When backing up near a wall/obstacle, the auto-brake seems to kick in when anything is closer than three or four feet away from the bumper. I use my mirrors and have an accurate impression of where the four corners of the vehicle are - I don't need the computer slamming on the brakes when I am reversing in a tight spot. It feels _more_ dangerous and I fear that one day, my knee-jerk reaction will be to fight the machine (press the gas harder, or get distracted looking at the console which emits lights and sounds every single time auto-brake kicks in) and wind up wrecking with even more force than I might have otherwise. Also, in traffic, I'll often take my foot off the gas and coast/idle, letting the vehicle slow down naturally. I try to do this instead of braking sometimes as I believe it assists with keeping the flow of traffic predictable for others. Usually this is no problem because I follow the next person at a safe distance. Sometimes, while decelerating as described above, I will allow the distance between myself and the next car to close, for example, if they're turning and will be gone in a second anyway. The Subaru then ruins my slowdown maneuver by slamming on the brakes because it thinks I'm approaching the vehicle ahead of me too quickly. Well, yes, maybe, but they're also halfway out of the lane already so it's not terribly significant that I'm closing the distance. Another half-second and they'll be gone, restoring my follow distance. (This has only happened once or twice but I imagine it gives the person behind me quite the unnecessary shock.) I wish there was a way to fine-tune the sensitivity, or at least an option to say "I am an attentive driver, please switch auto-brake to a lower sensitivity level." Currently the only option is to disable it each time the engine starts, which feels wrong to do...

s0rce 4y ago
I just bought a 2023 Crosstrek and haven't really noticed it kicking on too aggressively, it does beep sometimes. The only time I get annoyed is when its in adaptive cruise control and someone is merging off the highway it will think they are slowing a lot but its clear they will be out of the way.
- branon 4y ago
  Same experience. ACC doesn't brake anywhere near as hard as the emergency auto-brake, but when ACC is enabled and the car in front flips their blinker on and starts moving, I have to proactively feather the gas, otherwise ACC will ride the brakes until they have completely exited the lane. Past that, ACC is a godsend, should be standard everywhere. Lane keep assist also works impressively well (the proactive one that steers for you, there's another "emergency" lane keep system that will haul you back onto the road if you start to veer off, which I've never had the pleasure of using) Emergency auto-brake is _scary_ though. When it kicks in, the brakes make this horrible grinding sound, and you can tell the vehicle is stopping with all its might. You feel like you've done something wrong even if it's clear that the maneuver was safe.
  - s0rce 4y ago
    ACC was the primary reason I got a new car, and the used market was irrational.
jacurtis 4y ago
I have a 2022 BMW X4 and it handles it really well. It actually prevented me from rear-ending someone earlier this year. I have never had it kick in "accidentally". The lane departure can be slightly more aggressive. It generally works very well, but I have had a few cases where old road lines (think construction zone) caused it to veer into oncoming traffic. It has happened twice. Luckily I keep my hands on the steering wheel and it feels the resistance and submits to my judgement. But for all those people that drive with their knees or text while driving, it could be problematic. I'm comparing this to a 2020 F-150 Platinum that I had previously. It's automatic braking was awful. It had false alarms constantly. The lane departure was equally horrible. I find it interesting that the article pointed out how specifically terrible pickup trucks are with automatic braking technology and I thought back to my F-150. Since the F150 is the most common truck on the road (actually the most common vehicle in America period), I wonder how much of that statistic is being dragged down by Ford's terrible technology alone. Everyone I know with that on an F150 has turned it off because its so bad. I think the brand and implementation of this technology is very brand-specific. I have driven my parent's 2021 VW Atlas quite a bit which is equipped with both technologies and it is "fine". Not great and not bad. I've seen a few false alarms already in the shorter amount of time I have been in it. They were constant in the Ford and I have yet to experience one after 12 months of daily driving in the BMW.
- coredog64 4y ago
  Pickups are hard to get right. If you’re larping with an empty truck, the tail end is likely to come unglued if you brake too hard. If you tune it for normies, then loaded trucks will have longer stopping distances.
- MarcoZavala 4y ago
admax88qqq 4y ago
Or just leave more space on the highway when someone is turning? Auto brake isn't just for "inattentive" drivers. It's also for self proclaimed "attentive" drivers that can still lose focus at a bad instant. A turning car can still slam in their brakes when they're not completely out of your lane. Its rare, so your maneuver will be fine most of the time. But sometimes other drivers do unexpected things.
- branon 4y ago
  Fair enough, could definitely happen. I figure I _do_ still leave enough space even when closing though. I've never wrecked a car yet, so I tend to doubt the machine when it challenges a what I'm pretty sure is a well-refined heuristic.
  - pwinnski 4y ago
    Everybody who ever wrecks a car has "never wrecked a car yet" right up to that point.
    - branon 4y ago
      Totally fair. If (when!) the day comes, hopefully it will have been for some other reason instead of a maneuver I incorrectly thought was safe. I trust myself enough to think this will be the case.
- brookst 4y ago
  And if someone is following you too closely, but the lane to your left is clear, so it is in your interest to absorb the slack from someone in front of you turning because you can swerve left if they do something unexpected? I don't think anyone would complain about these systems if they had all of the context and made good decisions. But it is a problem when either humans or automated systems stand on the brakes based solely on what is in front, without regard for sides or rear. I do believe these systems are a net win. But they have rough edges that at least cause a lot of near-accidents because they don't behave the way drivers expect each other to.
CydeWeys 4y ago
Honestly, I feel like a lot of the people complaining about this feature are just bad drivers who regularly drive unsafely and are now getting called out on it. This in particular: > Sometimes, though, I will allow the distance between myself and the next car to close, for example, if they're turning and will be gone in a second anyway. The Subaru then ruins my well-calculated slowdown maneuver by slamming on the brakes because it thinks I'm approaching the vehicle ahead of me too quickly. Well, yes, maybe, but they're also halfway out of the lane already so it's not terribly significant that I'm only one car-length away and still going 40 MPH. Another half-second and they'll be gone, restoring my follow distance. You really shouldn't be driving like that. You don't know if the car in front of you making that turn is going to brake suddenly, like because, I dunno, they suddenly see a pedestrian crossing on the side street. Personally, I'm a more reserved (I guess safer?) driver, and I always leave good following distance and brake predictably in order to do so, and I can't say I've had problems with these systems. And I'm 100% in favor of systems that force other drivers on the road to drive more safely as well. Now if only they could prevent tailgating entirely ...
- branon 4y ago
  That was just one example. I've clarified my original comment, previously I was using the term "car length" in a way that did not make sense to others. I should have said "seconds of follow distance" All of this is infinitely nuanced anyway. There might not be a side street. It can happen on the highway too when cars switch lanes to exit. And it's not like it happens every day, it's fairly rare, I just have yet to actually _need_ the car to do it, by a fairly wide margin. 1-2 car lengths (not in literal units of 15-feet each, I mean one or two _seconds_ of follow distance minimum after accounting for speed/traffic/weather) going the speed limit with my foot off the gas and over the brake, paying attention ready to slow down fast in case of a contingency feels very safe to me. Again, pretty nuanced, this only lasts for a handful of seconds while the lead car completes their maneuver. The salient point is that I already do what the machine tries to replicate, I don't need my maneuver clobbered by another system.
  - DiggyJohnson 4y ago
    I’m not comfortable at all claiming that you’re a bad driver in general, like the GP proposes, and maybe I’m taking your unit of measurement too literally, but I don’t think 1-2 car lengths is a reasonable follow distance in almost any circumstances above 45mph, two lengths is kinda the minimum to not bother the person in front of you. Again, I’m making a very general statement, that might not apply to the situations you’re describing. And I’m a young guy that is working on being a more conservative driver myself - so I’m chuckling to myself just at the idea of me taking this side of the discussion.
giraffe_lady 4y ago
All I can think about is that poll showing that 90% of people think of themselves as above-average drivers. The autobraking isn't getting in your way and you don't need it, it's exactly for you lmao.
- brookst 4y ago
  Lol, my jeep that auto-brakes for parked cars in garages. Tell me again what I'm doing wrong by going 5mph in a parking garage?
  - giraffe_lady 4y ago
    I'm not here to defend every occurrence of an automated system firing. I'm pointing out that people who think they are attentive and skilled enough to not need these aids are exactly the people who should be using them.
    - branon 4y ago
      Fair enough. I don't believe I fall into that category though, it's not so much that I consider myself skilled enough that the safety system isn't necessary, but rather that I wish I could adjust sensitivity, because I like the idea of the system in general. In this vehicle I'm only able to disable it entirely (which seems unsafe to do, so I keep it on). Ideally I'd like to have it disabled only when reversing. Between the backup camera, mirrors, and the rear window, the safety systems are already present. The rear bumper really does not need to be triggering emergency brakes imo. The front bumper though - yeah that one should probably stay on, even if it annoys me sometimes.
Workaccount2 4y ago
Funny story, My sister got annoyed with the auto-braking on her new Subaru and turned it off. Three days later she rear ended someone, smashing up the whole front of her car. This was the third time she had rear ended someone. She keeps it on now.
- alphabettsy 4y ago
  > This was the third time she had rear ended someone. Pretty wild. Seems like license suspension or retraining should be required.
  - Merad 4y ago
    If only. My grandad was a lifelong truck driver and a pretty good one AFAIK, he kept working well into his 70s with a safe driving record. But eventually as he got older he caused three minor accidents in less than a year before he agreed to stop driving. This was in the late 00's as he was approaching 90.
  - Workaccount2 4y ago
    Knowing her, it's "Put your fucking phone down".
- MarcoZavala 4y ago
brookst 4y ago
2020 Jeep here. I used to park in a garage where I had to go 4mph or less, because at 5mph and above auto-braking would trigger every time I got to the end of a row and a car had backed in so its headlights were facing me. Scared the bejesus out of me, over and over. Also the same issue coming up on turning cars that will be gone momentarily. I'm ready to brake if they suddenly stop, but the system freaks the hell out and tries to get me rear-ended. I am willing to believe that there is a net reduction in crash likelihood because it may save me one time that I would have crashed. But the cost is a constant low-level fear of surprise and terror from normal driving. At least it's better than the 2014 Audi I had that would slam on the brakes on the freeway if there was a semi trailer going slow one lane to my right. I learned to keep one foot on the gas and ready to floor it when that happened (maybe 5-10 times a year).
dazc 4y ago
> 'Sometimes, though, I will allow the distance between myself and the next car to close, for example, if they're turning and will be gone in a second...' I often wonder what advantage in life people think they are gaining by this behaviour. Care to share?
- brookst 4y ago
  Reducing the odds of getting rear-ended by absorbing the slack of a conservative following distance rather than braking to maintain the same following distance from 35 to 20 mph.
  - dazc 4y ago
    Thanks for answering. Don't do this in some parts of the UK though, where 'crash for cash' is a thing, you may well become a victim. https://www.abi.org.uk/products-and-issues/topics-and-issues/fraud/crash-for-cash/ https://www.abi.org.uk/products-and-issues/topics-and-issues...
  - notacoward 4y ago
    You can't control what the person behind you does, but you can control what you do and rushing people through turns is unsafe. If the person in front of you signaled (or did anything else to indicate) their turn in sufficient time, then you should be able to do likewise for the person behind you with a light tap on the brakes. The odds of being rear-ended probably won't change by any significant amount, and IMX people who cite those odds weren't really thinking about them at the time. It's just an excuse for prioritizing speed over safety.
    - brookst 4y ago
      These systems are imperfect. People are imperfect, too. But please consider that not everything is evidence that everyone else is reckless driver. One day your system will fail in a surprising/dangerous way, and you'll tell someone "wow, it mistook a reflection for tail lights", and they'll say "well I am a perfectly safe driver so that could never happen with my careful driving, you must have been really reckless", and you'll have an epiphany.
code_duck 4y ago
This reminds me of the auto-correction feature on my insulin pump. Insulin dosage can be seen like braking: a certain brake pressure/duration decreases velocity over a period of time, and a specific amount of insulin decreases blood glucose over a period of time. My problem with the feature has been similar - it steps on the brakes too soon when I don’t need or expect it to. It can be adjusted, but in braking terms, one can adjust the pressure but not when it brakes. While this is touted as a cutting edge feature and many people like it, I had to turn it off.
ezfe 4y ago
I've got a 2020 Subaru Crosstrek and: 1. Forward collision alarm goes off falsely sometimes, but never the actual braking 2. Rear collision braking is usually fine as well, but since it doesn't realize grass/bushes aren't solid it feels a little more intense in those situations. It really feels like you're just driving recklessly.
giantg2 4y ago
"I'm only one car-length away and still going 40 MPH. Another half-second and they'll be gone," These numbers must be wrong, and are terribly unsafe. Just off the top of my head, that's like travelling 60fps for .5 seconds is 30 feet, which exceeds 1 car length, even for my truck.
- branon 4y ago
  Assuming that a "car length" is always equal to the length of a car is the unsafe bit. A car length is simply the minimum safe follow distance based on weather, traffic, and speed. To my mind it has almost nothing to do with the literal length of a car.
  - giantg2 4y ago
    Please provide a source for that definition. I've never seen that used anywhere.
    - branon 4y ago
      I don't have a source, it's just what makes sense to me - which at the end of the day, is how we all drive. As far as definitions for "car length" go, I feel that "average length of an actual car" is just as open to interpretation as "minimum safe length at which to follow a car" - really, these are both non-definitions. Today I've learned NEVER to reference "car length" online because it's a shitty and imprecise unit of measurement. In the future I will simply say "appropriate follow distance" even though that's highly variable too.
      - giantg2 4y ago
        You could use actual distances with speed, or seconds behind. Either one can be an appropriate measurement and are used in things like Driver Ed courses. Car length may be variable, but is colloquially understood to be 15' give or take, but not more than 20'.
      - pwinnski 4y ago
indymike 4y ago
> It's too sensitive and tends to brake shockingly hard during fairly mundane maneuvers. I've had a Crosstrek since 2018, and it has prevented accidents for me at least 4 times. It can be annoying when someone edges into your lane, or is edging out of your lane (and usually braking), but for every time it autobrakes for that, there's probably a situation where I'm glad it did. I'm sure the tech will just get better over time.
nawgz 4y ago
Also driving a 2021 Subaru, and I find it only rarely triggers incorrectly. The turning example you give, in my opinion, is a prime example of something really quite risky all drivers do, but it's quite simple for that person to tap the brakes and then you'll cause an accident. Otherwise, with the wall, maybe your system is misconfigured; I've tested mine pretty well and at low speeds like when parking or reversing it has never triggered until I'm within 1ft of walls or bushes The worst example was when a bird flew in front of me and the car decided that was an imminent accident, but otherwise I think if you loosened the tuning it would be unlikely to be so effective. BTW: 0 accident driver before and after this vehicle
pwinnski 4y ago
"Over-sensitive" or not, what's the actual harm in driving in a way that avoids triggering it? When your driving safety system gives you feedback while driving, you have two choices: - Learn from the system and modify your driving to be safer for yourself and those around you, or - Ignore the system, describe it as "too sensitive," and disable it. Before the driving safety system feedback, you might have been an unsafe driver out of ignorance. After the driving safety system feedback, you're choosing to be an unsafe driver willfully.
- branon 4y ago
  This is fair. I do (and have) adjusted my behavior to avoid setting off the auto-brake. Mainly I did this because disabling it entirely seemed like a bad idea, despite my misgivings. Sometimes I still trigger it when reversing towards obstacles though. It still prompts an eyeroll and a muttered curse. Not sure if that will ever go away, somebody else mentioned that it tends to treat bushes as solid objects. Not that I'm reversing over top of the bushes, but reversing _towards_ them should not be as big of a problem as the auto-brake would have the driver believe.

by branon 4y ago

s0rce 4y ago

I just bought a 2023 Crosstrek and haven't really noticed it kicking on too aggressively, it does beep sometimes. The only time I get annoyed is when its in adaptive cruise control and someone is merging off the highway it will think they are slowing a lot but its clear they will be out of the way.

branon 4y ago
Same experience. ACC doesn't brake anywhere near as hard as the emergency auto-brake, but when ACC is enabled and the car in front flips their blinker on and starts moving, I have to proactively feather the gas, otherwise ACC will ride the brakes until they have completely exited the lane. Past that, ACC is a godsend, should be standard everywhere. Lane keep assist also works impressively well (the proactive one that steers for you, there's another "emergency" lane keep system that will haul you back onto the road if you start to veer off, which I've never had the pleasure of using) Emergency auto-brake is _scary_ though. When it kicks in, the brakes make this horrible grinding sound, and you can tell the vehicle is stopping with all its might. You feel like you've done something wrong even if it's clear that the maneuver was safe.
- s0rce 4y ago
  ACC was the primary reason I got a new car, and the used market was irrational.

jacurtis 4y ago

I have a 2022 BMW X4 and it handles it really well. It actually prevented me from rear-ending someone earlier this year. I have never had it kick in "accidentally". The lane departure can be slightly more aggressive. It generally works very well, but I have had a few cases where old road lines (think construction zone) caused it to veer into oncoming traffic. It has happened twice. Luckily I keep my hands on the steering wheel and it feels the resistance and submits to my judgement. But for all those people that drive with their knees or text while driving, it could be problematic. I'm comparing this to a 2020 F-150 Platinum that I had previously. It's automatic braking was awful. It had false alarms constantly. The lane departure was equally horrible. I find it interesting that the article pointed out how specifically terrible pickup trucks are with automatic braking technology and I thought back to my F-150. Since the F150 is the most common truck on the road (actually the most common vehicle in America period), I wonder how much of that statistic is being dragged down by Ford's terrible technology alone. Everyone I know with that on an F150 has turned it off because its so bad. I think the brand and implementation of this technology is very brand-specific. I have driven my parent's 2021 VW Atlas quite a bit which is equipped with both technologies and it is "fine". Not great and not bad. I've seen a few false alarms already in the shorter amount of time I have been in it. They were constant in the Ford and I have yet to experience one after 12 months of daily driving in the BMW.

coredog64 4y ago
Pickups are hard to get right. If you’re larping with an empty truck, the tail end is likely to come unglued if you brake too hard. If you tune it for normies, then loaded trucks will have longer stopping distances.
MarcoZavala 4y ago

admax88qqq 4y ago

Or just leave more space on the highway when someone is turning? Auto brake isn't just for "inattentive" drivers. It's also for self proclaimed "attentive" drivers that can still lose focus at a bad instant. A turning car can still slam in their brakes when they're not completely out of your lane. Its rare, so your maneuver will be fine most of the time. But sometimes other drivers do unexpected things.

branon 4y ago
Fair enough, could definitely happen. I figure I _do_ still leave enough space even when closing though. I've never wrecked a car yet, so I tend to doubt the machine when it challenges a what I'm pretty sure is a well-refined heuristic.
- pwinnski 4y ago
  Everybody who ever wrecks a car has "never wrecked a car yet" right up to that point.
  - branon 4y ago
    Totally fair. If (when!) the day comes, hopefully it will have been for some other reason instead of a maneuver I incorrectly thought was safe. I trust myself enough to think this will be the case.
brookst 4y ago
And if someone is following you too closely, but the lane to your left is clear, so it is in your interest to absorb the slack from someone in front of you turning because you can swerve left if they do something unexpected? I don't think anyone would complain about these systems if they had all of the context and made good decisions. But it is a problem when either humans or automated systems stand on the brakes based solely on what is in front, without regard for sides or rear. I do believe these systems are a net win. But they have rough edges that at least cause a lot of near-accidents because they don't behave the way drivers expect each other to.

CydeWeys 4y ago

Honestly, I feel like a lot of the people complaining about this feature are just bad drivers who regularly drive unsafely and are now getting called out on it. This in particular: > Sometimes, though, I will allow the distance between myself and the next car to close, for example, if they're turning and will be gone in a second anyway. The Subaru then ruins my well-calculated slowdown maneuver by slamming on the brakes because it thinks I'm approaching the vehicle ahead of me too quickly. Well, yes, maybe, but they're also halfway out of the lane already so it's not terribly significant that I'm only one car-length away and still going 40 MPH. Another half-second and they'll be gone, restoring my follow distance. You really shouldn't be driving like that. You don't know if the car in front of you making that turn is going to brake suddenly, like because, I dunno, they suddenly see a pedestrian crossing on the side street. Personally, I'm a more reserved (I guess safer?) driver, and I always leave good following distance and brake predictably in order to do so, and I can't say I've had problems with these systems. And I'm 100% in favor of systems that force other drivers on the road to drive more safely as well. Now if only they could prevent tailgating entirely ...

branon 4y ago
That was just one example. I've clarified my original comment, previously I was using the term "car length" in a way that did not make sense to others. I should have said "seconds of follow distance" All of this is infinitely nuanced anyway. There might not be a side street. It can happen on the highway too when cars switch lanes to exit. And it's not like it happens every day, it's fairly rare, I just have yet to actually _need_ the car to do it, by a fairly wide margin. 1-2 car lengths (not in literal units of 15-feet each, I mean one or two _seconds_ of follow distance minimum after accounting for speed/traffic/weather) going the speed limit with my foot off the gas and over the brake, paying attention ready to slow down fast in case of a contingency feels very safe to me. Again, pretty nuanced, this only lasts for a handful of seconds while the lead car completes their maneuver. The salient point is that I already do what the machine tries to replicate, I don't need my maneuver clobbered by another system.
- DiggyJohnson 4y ago
  I’m not comfortable at all claiming that you’re a bad driver in general, like the GP proposes, and maybe I’m taking your unit of measurement too literally, but I don’t think 1-2 car lengths is a reasonable follow distance in almost any circumstances above 45mph, two lengths is kinda the minimum to not bother the person in front of you. Again, I’m making a very general statement, that might not apply to the situations you’re describing. And I’m a young guy that is working on being a more conservative driver myself - so I’m chuckling to myself just at the idea of me taking this side of the discussion.

giraffe_lady 4y ago

All I can think about is that poll showing that 90% of people think of themselves as above-average drivers. The autobraking isn't getting in your way and you don't need it, it's exactly for you lmao.

brookst 4y ago
Lol, my jeep that auto-brakes for parked cars in garages. Tell me again what I'm doing wrong by going 5mph in a parking garage?
- giraffe_lady 4y ago
  I'm not here to defend every occurrence of an automated system firing. I'm pointing out that people who think they are attentive and skilled enough to not need these aids are exactly the people who should be using them.
  - branon 4y ago
    Fair enough. I don't believe I fall into that category though, it's not so much that I consider myself skilled enough that the safety system isn't necessary, but rather that I wish I could adjust sensitivity, because I like the idea of the system in general. In this vehicle I'm only able to disable it entirely (which seems unsafe to do, so I keep it on). Ideally I'd like to have it disabled only when reversing. Between the backup camera, mirrors, and the rear window, the safety systems are already present. The rear bumper really does not need to be triggering emergency brakes imo. The front bumper though - yeah that one should probably stay on, even if it annoys me sometimes.

Workaccount2 4y ago

Funny story, My sister got annoyed with the auto-braking on her new Subaru and turned it off. Three days later she rear ended someone, smashing up the whole front of her car. This was the third time she had rear ended someone. She keeps it on now.

alphabettsy 4y ago
> This was the third time she had rear ended someone. Pretty wild. Seems like license suspension or retraining should be required.
- Merad 4y ago
  If only. My grandad was a lifelong truck driver and a pretty good one AFAIK, he kept working well into his 70s with a safe driving record. But eventually as he got older he caused three minor accidents in less than a year before he agreed to stop driving. This was in the late 00's as he was approaching 90.
- Workaccount2 4y ago
  Knowing her, it's "Put your fucking phone down".
MarcoZavala 4y ago

brookst 4y ago

2020 Jeep here. I used to park in a garage where I had to go 4mph or less, because at 5mph and above auto-braking would trigger every time I got to the end of a row and a car had backed in so its headlights were facing me. Scared the bejesus out of me, over and over. Also the same issue coming up on turning cars that will be gone momentarily. I'm ready to brake if they suddenly stop, but the system freaks the hell out and tries to get me rear-ended. I am willing to believe that there is a net reduction in crash likelihood because it may save me one time that I would have crashed. But the cost is a constant low-level fear of surprise and terror from normal driving. At least it's better than the 2014 Audi I had that would slam on the brakes on the freeway if there was a semi trailer going slow one lane to my right. I learned to keep one foot on the gas and ready to floor it when that happened (maybe 5-10 times a year).

dazc 4y ago

> 'Sometimes, though, I will allow the distance between myself and the next car to close, for example, if they're turning and will be gone in a second...' I often wonder what advantage in life people think they are gaining by this behaviour. Care to share?

brookst 4y ago
Reducing the odds of getting rear-ended by absorbing the slack of a conservative following distance rather than braking to maintain the same following distance from 35 to 20 mph.
- dazc 4y ago
  Thanks for answering. Don't do this in some parts of the UK though, where 'crash for cash' is a thing, you may well become a victim. https://www.abi.org.uk/products-and-issues/topics-and-issues/fraud/crash-for-cash/ https://www.abi.org.uk/products-and-issues/topics-and-issues...
- notacoward 4y ago
  You can't control what the person behind you does, but you can control what you do and rushing people through turns is unsafe. If the person in front of you signaled (or did anything else to indicate) their turn in sufficient time, then you should be able to do likewise for the person behind you with a light tap on the brakes. The odds of being rear-ended probably won't change by any significant amount, and IMX people who cite those odds weren't really thinking about them at the time. It's just an excuse for prioritizing speed over safety.
  - brookst 4y ago
    These systems are imperfect. People are imperfect, too. But please consider that not everything is evidence that everyone else is reckless driver. One day your system will fail in a surprising/dangerous way, and you'll tell someone "wow, it mistook a reflection for tail lights", and they'll say "well I am a perfectly safe driver so that could never happen with my careful driving, you must have been really reckless", and you'll have an epiphany.

code_duck 4y ago

This reminds me of the auto-correction feature on my insulin pump. Insulin dosage can be seen like braking: a certain brake pressure/duration decreases velocity over a period of time, and a specific amount of insulin decreases blood glucose over a period of time. My problem with the feature has been similar - it steps on the brakes too soon when I don’t need or expect it to. It can be adjusted, but in braking terms, one can adjust the pressure but not when it brakes. While this is touted as a cutting edge feature and many people like it, I had to turn it off.

ezfe 4y ago

I've got a 2020 Subaru Crosstrek and: 1. Forward collision alarm goes off falsely sometimes, but never the actual braking 2. Rear collision braking is usually fine as well, but since it doesn't realize grass/bushes aren't solid it feels a little more intense in those situations. It really feels like you're just driving recklessly.

giantg2 4y ago

"I'm only one car-length away and still going 40 MPH. Another half-second and they'll be gone," These numbers must be wrong, and are terribly unsafe. Just off the top of my head, that's like travelling 60fps for .5 seconds is 30 feet, which exceeds 1 car length, even for my truck.

branon 4y ago
Assuming that a "car length" is always equal to the length of a car is the unsafe bit. A car length is simply the minimum safe follow distance based on weather, traffic, and speed. To my mind it has almost nothing to do with the literal length of a car.
- giantg2 4y ago
  Please provide a source for that definition. I've never seen that used anywhere.
  - branon 4y ago
    I don't have a source, it's just what makes sense to me - which at the end of the day, is how we all drive. As far as definitions for "car length" go, I feel that "average length of an actual car" is just as open to interpretation as "minimum safe length at which to follow a car" - really, these are both non-definitions. Today I've learned NEVER to reference "car length" online because it's a shitty and imprecise unit of measurement. In the future I will simply say "appropriate follow distance" even though that's highly variable too.
    - giantg2 4y ago
      You could use actual distances with speed, or seconds behind. Either one can be an appropriate measurement and are used in things like Driver Ed courses. Car length may be variable, but is colloquially understood to be 15' give or take, but not more than 20'.
    - pwinnski 4y ago

indymike 4y ago

> It's too sensitive and tends to brake shockingly hard during fairly mundane maneuvers. I've had a Crosstrek since 2018, and it has prevented accidents for me at least 4 times. It can be annoying when someone edges into your lane, or is edging out of your lane (and usually braking), but for every time it autobrakes for that, there's probably a situation where I'm glad it did. I'm sure the tech will just get better over time.

nawgz 4y ago

Also driving a 2021 Subaru, and I find it only rarely triggers incorrectly. The turning example you give, in my opinion, is a prime example of something really quite risky all drivers do, but it's quite simple for that person to tap the brakes and then you'll cause an accident. Otherwise, with the wall, maybe your system is misconfigured; I've tested mine pretty well and at low speeds like when parking or reversing it has never triggered until I'm within 1ft of walls or bushes The worst example was when a bird flew in front of me and the car decided that was an imminent accident, but otherwise I think if you loosened the tuning it would be unlikely to be so effective. BTW: 0 accident driver before and after this vehicle

pwinnski 4y ago

"Over-sensitive" or not, what's the actual harm in driving in a way that avoids triggering it? When your driving safety system gives you feedback while driving, you have two choices: - Learn from the system and modify your driving to be safer for yourself and those around you, or - Ignore the system, describe it as "too sensitive," and disable it. Before the driving safety system feedback, you might have been an unsafe driver out of ignorance. After the driving safety system feedback, you're choosing to be an unsafe driver willfully.

branon 4y ago
This is fair. I do (and have) adjusted my behavior to avoid setting off the auto-brake. Mainly I did this because disabling it entirely seemed like a bad idea, despite my misgivings. Sometimes I still trigger it when reversing towards obstacles though. It still prompts an eyeroll and a muttered curse. Not sure if that will ever go away, somebody else mentioned that it tends to treat bushes as solid objects. Not that I'm reversing over top of the bushes, but reversing _towards_ them should not be as big of a problem as the auto-brake would have the driver believe.