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Studies find automatic braking can cut crashes over 40%

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Re: Studies find automatic braking can cut crashes over 40%

#51

Post by dazc »

branon wrote: post #10

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…

> '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?

Re: Studies find automatic braking can cut crashes over 40%

#52

Post by mgraupner »

WXLCKNO wrote: post #38

Got a new M340i a month ago, first day driving it I get cut off by some 90 year old in a buick who didn't want to miss his turn. Was really glad to have automatic braking, by the time my foot had lifted off the gas it was already braking.

Such a great feature, both of my last cars had this "presense" breaking. I was never really in a situation where it was critical, but the feeling that the breaks are already in a ready state (touch it slightly and you knew a little bit more will do hard breaking instead of going all the way) when I was touching it felt pretty reassuring and a little magic at the same time.

Re: Studies find automatic braking can cut crashes over 40%

#53

Post by branon »

DiggyJohnson wrote: post #45
branon wrote: post #33

Earlier quoted context omitted.

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 ac…

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…

This is an interesting point. The Subaru's adaptive cruise control system treats a "car length" as a fairly large unit of measurement. One car length seems to be the literal length of the vehicle, plus some reasonable amount of buffer on both ends. Probably twice as large as the vehicle itself. And the faster you're going, the larger a single car length becomes. Infinite nuance :P

But in general, very good commentary on systems that provide useful feedback for the human operator versus ones that don't. ACC makes it clear what a car length should be, and if you're paying attention you can gauge how much more space it leaves when you're moving fast. So that's what I go by.

Re: Studies find automatic braking can cut crashes over 40%

#54

Post by grog454 »

bhouston wrote: post #2

It feels like a simple thing but I also suspect it is effective from my personal experience. We have automatic braking (fixed: breaking) on my Toyota Rav4: https://www.youtube.com/watch?v=gbnoFbb8G8Q It is a simple thing but the PCS has been triggered 4 times in the last 5 years and never incorrectly. I think I would have stopped soon enough without it (as I've never hit anything in my 20+ years of driving), but it w…

> You shouldn't need it if everything else goes perfectly, but it doesn't hurt to have it.

That's not how I see it. Computers react faster than humans even setting aside the mechanical delay of lifting your foot, moving it, and pressing it down again.

It's more like running a linter on your code. 99.99% of the time it isn't necessary and you already knew what it was going to say, but the one time it does catch something important it's a life saver.

Re: Studies find automatic braking can cut crashes over 40%

#55

Post by ezfe »

consp wrote: post #7
bhouston wrote: post #2

It feels like a simple thing but I also suspect it is effective from my personal experience. We have automatic braking (fixed: breaking) on my Toyota Rav4: https://www.youtube.com/watch?v=gbnoFbb8G8Q It is a simple thing but the PCS has been triggered 4 times in the last 5 years and never incorrectly. I think I would have stopped soon enough without it (as I've never hit anything in my 20+ years of driving), but it w…

My car (not a toyota) does it too and I've never had it actually brake but the very audible + visual warning signs definitely makes you act tiny fraction sooner (at least that is how it feels). I'm pretty sure it would have stopped otherwise on its own but a bit less pleasant. edit: it also triggers when you go down a steep parking lot onto a flat surface a bit too fast which is interesting but at least valid (with r…

Yup, the fact it chimes in at a lower confidence reduces the negative effects of any false positive. It needs to be very confident to start applying braking, but it also primes your brakes before that so if you slam on the brakes from the chime it gets them to 100% instantly.

Re: Studies find automatic braking can cut crashes over 40%

#56

Post by brookst »

admax88qqq wrote: post #25
branon wrote: post #10

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…

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.

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.

Re: Studies find automatic braking can cut crashes over 40%

#57

Post by BeetleB »

dsfyu404ed wrote: post #18
consp wrote: post #13

Earlier quoted context omitted.

> who will pay The person hitting you from behind would be at fault anyway, at least where I live you are required to keep enough distance to stop even for no apparent reason, if driving in a lane and not moving to another. If you do it whilst moving in front of another car as it could be on you as you are required to yield and leave enough space to not hinder or endanger the driving of the other vehicle. This also i…

The rules for accident liability aren't as rigid and naive as you are implying. The rear ender having to pay is just the base case that is used in the absence of other facts. If you drive "in an asinine manner" (the definition of asinine is subject to discretion and negotiation between the relevant insurance companies) and manage to make the front of someone else's care meet the rear of yours in the process AND there…

It probably varies by state, but people I know who've rear ended someone else have said that no one is interested in how it happened. The cops didn't care, and the insurance didn't care. The rule is it's your responsibility to maintain a safe distance.

So sure - the guy in front of you may have been extremely reckless, but no one involved is even going to want to hear that narrative.

Re: Studies find automatic braking can cut crashes over 40%

#59

Post by code_duck »

branon wrote: post #10

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…

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.

Re: Studies find automatic braking can cut crashes over 40%

#60

Post by ezfe »

branon wrote: post #10

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…

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.

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