Hacker News Reader

Comment by Retric | Hacker News Reader

You’re describing and absolute failure of the ABS system. If your car has such a massive flaw little else matters, it’s inherently unsafe. Granted, if you had turned off whatever version of vehicle stability assistance came with the car and ABS had some major defect it’s possible, but again at that point you’re describing several failures.

I don’t mean to suggest the AEB system is without flaws, but if applying sudden breaking cause the break lines to rupture or whatever, that’s a serious failure on it’s own.

View on HN

Breaking hard loads weight onto the front tyres, which changes handling in every car ever. My car breaking (unexpectedly) when I'm maneuvering (eg around an object) means I have no idea who is responsible for the outcome. My decision was overridden by the car.

Same is true of ABS and traction control, if you take the view that your decision was to apply this much braking or power to the wheels.

Yet ABS and traction/stability control are safer for the vast majority of drivers (who are terribly poorly trained on vehicle dynamics).

>Same is true of ABS and traction control,

I have to disagree. After using a car in various slippery conditions the way ABS and traction control works is very predictable. This new system is more like an airbag than ABS. You can't really test it in a controlled environment and get familiar with it. You will be surprised when it activates. The key question everyone is asking is: is it going to be a positive surprise or a negative one?

Try ABS on gravel or sandy soil or most traction control systems on wet leaves. It's easy to find a situation where the direct driver input would be preferred over the nanny systems over-riding. (I do agree that overall, they improve safety.)

It may be easy for you, but I've had a tough time outperforming ABS on ice and leaves. And the ABS of today is better than the ABS of the '90s. In pretty much every case where I've done real-world emergency hard braking I have either appreciated ABS or wished it was there. The last time I drove a vehicle without ABS was riding a motorcycle; if ever there was a candidate for ABS it's motorcycles, yet surprisingly ABS has taken much longer to become standard on bikes. Did I manage to avoid plowing into a fool on the interstate? Yes, and it was thanks to the hours of self training on perfecting my braking technique. Would I prefer not to have worried about it at all, knowing that the bike would pulse the front wheel a hundred times a second and maintaining traction 95% of the time? Absolutely I would.

All of my traction tests on severe ice have shown that the ABS does about the same as I can, which is to say, terribly. Drivers should know that ABS can't stop a car that has no traction. That is an education problem, not an ABS problem. If you can reliably reproduce a case where ABS does worse than a driver with a few hours of training, I'm pretty sure that there are some organization that want to talk with you.

On any loose gravel drive [or most surfaces where a slid, it's trivial for an untrained driver to out brake an ABS-equipped car 9 (or 10) out of 10 times.

Try it sometime.

Or read the NHTSA study on it: http://www.nhtsa.gov/DOT/NHTSA/NRD/Multimedia/PDFs/VRTC/ca/c...

Mangled the text above; it should say “where a sliding tire deforms the surface]”

I maintain there is a fundamental difference between an electronic system which attempts to aid a car do what the driver has asked, and one which just puts the brakes on hard and without driver input.

I know what you're saying, but I think it's a false equivalence.

You’re describing and absolute failure of the ABS system.

In that scenario, braking hard enough to engage ABS at all is the failure. It is not a failure on ABS's part unless you consider all ABS faulty. Some loss of yaw control is inevitable whenever ABS is engaged. ABS only gives better yaw control than completely locking the wheels.

Going from “straight sections” of the road, applying breaks and getting:

> when the tires recover traction the whole car is angled 20 degrees to the left.

That’s not just some loss of yaw control. That’s an ABS system utterly failing to do it’s job. The point of an ABS system is to avoid the exact situation described.

That's pretty normal behavior, in my experience.

In that case, I honestly believe you may want to get a new vehicle, or at a minimum get yours checked by a competent mechanic. There have been plenty of advancements in ABS and traction control, but this is literally what they where designed to deal with.

Ex: https://m.youtube.com/watch?v=iz9_4qiSXkw

Especially if rather than stopping with a slight twist it’s twisting enough that hard breaking means you often lose control.

I don't think I have ever seen any vehicle whose ABS wasn't essentially rapid cadence braking, and in bad road conditions, the car will turn a bit during the intervals while the wheels are locked (so I generally found threshold braking more useful). If the road is bad enough, even leaving the wheels free won't necessarily keep the car pointed forward. That said, I haven't really had issues recovering from these situations.

Reply on news.ycombinator.com