Passive systems like ABS are pretty much the only thing I have ever found value in, and even then it's been a mixed bag when operating near limits. Never heard of a car locking up on the freeway because an ABS fuse went out...
Because human beings have such a terrible track record that even "dumb" computers running code written by shabby programmers can do better. Even with these errors the computers are still doing a better job. The NIH studied Automatic Emergency Braking systems and found that, "With a 100% market penetration rate, fatalities could be reduced by 13.2%, and injuries could be reduced by 9.1%."
That said... I had the rental because of an accident that would have been avoided if my own car had frontal collision detection and automatic braking. Assuming it had worked.
It either didn't have lane-centering or it was disabled, but I think in general that's a way more noticeable input than braking. If you have a weird input in steering (ie, a strong gust of wind) your instinct is to steer the opposite way, but in general I think most people that have weird input with acceleration/braking tend to respond with just braking universally.
We only have 1 side of this story - that a few people have been surprised and had accidents. We don’t have the stats on how many people the active braking has saved from a collision. (BTW I have a CRV, and have experienced sudden braking myself, both with and without something in front of me, but it hasn’t caused an accident yet.)
ABS is a computer between the brake and the physics, and there’s widespread agreement about the benefits of this arrangement. So maybe the problem isn’t the computer, or the idea to use them in the loop. Maybe the problem is an incomplete understanding of people, or maybe it’s just a sensor defect or manufacturing issue. (Which, I would agree, absolutely should be considered when plugging things into a computer controller.)
We have lots of computers in the physics loop, and very few of them give any of us pause. ECUs are standard these days and are critical to fuel efficiency and reducing environmental impact. Self driving cars are on the way and are a whole new level of computer control. I think I’m still in favor of self-driving cars and the potential they have to reduce traffic, collisions, and environmental impact...
Assume you are traveling down the 405 at 80mph during rush hour.
What is the worst case scenario for an ABS failure mode?
What is the worst case scenario for an emergency braking failure mode?
Okay, bad driving choice there. You are 1.5x more likely to die in a collision driving 80mph than if you were driving the speed limit (65mph), since collision energy is proportional to velocity squared. ;)
Worst case for ABS failure vs emergency braking failure? Seems like both can easily result in death, and I don’t see reasons yet to believe one is more likely than the other. We probably have a lot more data on the number of deaths lack of ABS has caused over the years than computer braking systems, and the good news is that we can fix computer braking systems right now and forever.
The big difference here is control, not outcome. Having brakes seize suddenly is surprising, whereas going from static to dynamic friction when slamming on the brakes isn’t very surprising. Of course we strive to minimize surprise, and of course it’s preferable if cars don’t slam on the brakes without cause.
In the article, there were several links at the bottom with stats on the impact on Volvo cars in the US: https://www.iihs.org/topics/bibliography/ref/2111. The stats aren't directly equivalent, but I think it helps to support your argument.
Unexpected surprises can be dangerous. I feel like safety related systems really should be as simple as possible.
I like ABS but in one of my vehicles I had an issue with it randomly engaging when it shouldn't due to rusted and cracked tone rings. It's actually pretty scary losing the majority of your braking power when you desperately need it.
Agreed. It's bad both ways. I would say the more dangerous failure mode is the one which results in the most unexpected amount of delta between input and output.
If you are already in the process of trying to stop, there is going to be some finite difference between expectation and reality, even if the braking system does not perform perfectly (or at all). Your brain is already thinking "ok let's find a way to slow this thing down". You might have a few precious milliseconds to go for a shoulder or other external soft-stop opportunity.
If you are inputting zero braking signal and receive a 100% stop force arbitrarily, that is pretty much an infinite level of surprise. Incidentally, this may also provoke any adjacent ABS failure modes.
I think it's a great idea for the driver behind me to have such a system. It makes them less likely to rear-end me.
> I think it's a great idea for the driver behind me to have such a system. It makes them less likely to rear-end me.
Yes. But it's a scary idea for the driver in front of you to have such a system. If they (their car) suddenly goes into hard braking for no visible reason on the highway, you might be rear-ending them.
Not really a world I'd prefer to live in.