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Comment by nxc18 | Hacker News Reader

Autonomous braking is a huge step, and, imho, more exciting at the moment than full autonomous driving because it can save lives right now, and is unlikely to take them (shots fired at Uber).

But buyer beware. Even within the IIHS safety standards, there is considerable variability. I love my Toyota Corolla (2017), but it's braking will only take a few mph off after warning you. I can't wait until my lease expires and I can upgrade to the Subaru (edit: or maybe the Volvo from TFA). Look up the videos, they are fully capable of stopping without any collision up to ~40 mph (disclaimer: never rely on these safety features, it's still your responsibility to be safe).

Do your research, happy and safe driving!

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I've also read enough complaints about inexplicable emergency braking activation to say that all drivers should be aware these are on the road. You need to consider that now random new cars may execute a "brake check" maneuver in situations where you would never anticipate a human to have done the same thing.

You should be expecting any driver to do an emergency stop right in front of you.

I've learned the hard way not to expect anything from other drivers on the road.

Make sure your following distance is such that you have enough time to react to completely oblivious driving behaviour from other drivers.

> Make sure your following distance is such that you have enough time to react to completely oblivious driving behavior from other drivers.

While I fully endorse this ideal, the reality of driving in high-traffic cities is that it's impossible. Every time you adjust to leave proper space, someone will come along and appropriate your safety buffer. When you slow again to allow enough space, the pattern repeats.

Tragedy of the driving commons. In such situations I just drive slightly under the distance I would normally keep, but then just back off those that do barge in.

I didn't say we should take these braking systems off the road, but I do think drivers need to adapt to their presence. Personally, I am happy my 2017 vehicle does not have it and the ones on the market will probably be much improved by the time I consider a replacement.

As others discussed throughout this thread, there are many situations where drivers violate the safe following distance rules. Aside from the lack of attention scenarios, I think many drivers take calculated risks to temporarily reduce their following distances while performing some other maneuver. They should incorporate this new idea of neurotic automatic-braking systems into this risk calculus, so they don't get caught in a situation they cannot handle.

While we have a mixture of different vintage cars (and drivers!), I am afraid we will remain living in interesting times...

I’ve thought about this and and I think the best thing to do here is to relentlessly keep a long, safe distance from vehicles ahead. There are just things you can’t possibly see that the driver before you can.(a puppy/squirrel/whatever that he wants to avoid killing, you can’t possibly know). You can’t anticipate what a human will do here.

You also give yourself a buffer when vehicle ahead have an emergency stop - imagine there’s a truck behind you.

I guess what I’m saying is these ‘brake checks’ are welcome, even if they only serve to educate people.

Problem is everybody else have to behave similarly, otherwise other cards just take the place of that safe distance.

It might be annoying, but even if a few cars get in between you usually don't lose much by getting a safe distance again.

I second this.

There are three scenarios if I'm not overtaking:

1) I'm going faster than the vehicle in front. In this case, it doesn't matter if another vehicle pulls in between us because I'm about to overtake anyway.

2) I'm going slower than the vehicle in front. In this case, it doesn't matter if another vehicle pulls in between us because I'm falling back and the gap is ever-increasing.

3) I'm going approximately the same speed as the vehicle in front. In this case, there tend to be two ways a vehicle pulls inbetween us:

a- it's merging from an on-slip-road (on-ramp?), in which case this doesn't happen often, and I'll just fall back or overtake b- it's just overtaken me, then slotted into a gap that's too small for it anyway. If the car has overtaken me, it's mostly because it wants to go faster (in which case it will probably vacate the space again soon) or it wants to pull off (in which case it will definitely vacate the space again).

If I am overtaking, then yes, someone may pull into the gap, but I'm still overtaking the vehicle I want to get past.

If you stop worrying about going 2mph faster than another lane of traffic, then leaving a safe gap is mostly pretty easy and stress-free. It will only take you 15 minutes longer to drive 200 miles at 65 than at 70.

Here in the UK, where we drive on the left and overtaking is only allowed to the right of slower vehicles under normal conditions, there are some other variations:

c- a vehicle in the lane to your left that you were going to overtake has itself caught up with a slower vehicle and wants to pull out to overtake it, moving into the gap in front of you

d- a vehicle with an impatient driver is undertaking traffic (passing to the left of slower vehicles) and then moves into the gap in front of you.

The first of these is a normal situation, but still results in a vehicle moving into the space in front of you, sometimes without accelerating up to your speed first. Fortunately, it's usually easy to anticipate this situation, and many drivers will helpfully drop back a little to allow more space for the other vehicle to move out.

The second of these is a result of aggressive and probably illegal driving, and is more of a problem because the driver cutting in may well be going too fast, move out into a space that isn't really wide enough, and then brake suddenly.

Still, in my experience these don't cause much delay if you're allowing a sensible gap in front. I find people who try to keep closer to the car in front to deter others from pulling into "their" space seem to get far more upset about these situations than I do.

(also in the UK) Completely agree with your closing remark. By and large, by deciding to not care about stopping cars getting in front of me, it doesn't bother me when they do. Any delay is completely negligible.

When this happens to me on my commute, I find it incredibly hilarious. Sometimes I wave at the driver through their rear-view when we are inevitably stopped at the same stoplight not 2 minutes later.

I find myself on both sides of this equation, sometimes "what a waste, why did this guy bother passing?", and sometimes "Phew, finally in front of THAT person"(even if we are stopped at the same light, but I'm now in front).

Reminds me of the George Carlin line: "anybody driving slower than you is an idiot, and anyone going faster than you is a maniac"

Agree. In Europe, if you follow the recommended safety distance, you always have the time to brake if anything happens to the car in front of you. The problem is that people do not follow them.

Following the recommended safety distance (2-3 seconds of travel distance if I recall correctly) is quite difficult in moderate to heavy traffic.

If you leave a large enough gap with the car in front, then people will merge into that gap. If you then slow down to create a new gap - people will overtake and merge in again. You end up travelling slower than the rest of traffic, with people overtaking and merging, which creates dangers in itself.

> I think the best thing to do here is to relentlessly keep a long, safe distance from vehicles ahead.

In Germany, this is legally required. However, the safety distance is often abused by other vehicles when passing.

This is just generally good advice and always has been. Don't drive too closely to stop safely.

Sudden curves in the road when there are parked cars is the biggest issue for mine. I think it plots a path based on how my wheel is turned. When there's a 10-15 degree kink in the road, I can't turn early or I'll cross the center line, so it thinks I'm going to continue straight into a parked car. Hasn't brought me to a complete stop, but it could certainly mess with a tailgater.

> but it could certainly mess with a tailgater.

Unless the tailgater also has this system!

Now I've got a hilarious image in my mind of a bunch of modern cars taking turns to accelerate, abruptly brake, accelerate, brake... The future is now.

That’s called a phantom jam, happens right now on 101 with humans;) Won’t happen if only people don’t tailgate.

[offtopic]Yep. I'm usually in the "slow lane" bemidst truckers, amusing myself by watching the Giant Car Worm on the "fast lane".[/offtopic]

Actually, if everyone perfectly tailgated out of a rolling jam, then they'd all be fine. Instead you get people that let a large enough gap open for them to accelerate faster than the car in front, then they have to brake when they reach that lead car again. This slinky effect is what causes those rolling traffic jams and why they can break them by slow-rolling in from of the jam to force everyone to stop the slinky effect.

I imagine phantom jams will pretty much be a thing of the past once we reach a certain percentage of cars running auto-braking cruise control. Have there been studies on what that percentage is?

You have to characterize the control behavior to model whether the system will dampen its response or create a sustained or amplifying feedback loop as all the agents interact. These traffic jams are essentially standing waves propagating between agents.

You don't erase the standing wave by having everybody maintain a fixed following distance or mimicking the speed of their leader. You need to predict future changes and allow the space to contract to help smooth out the transient disruptions and slowly rebound without over-shooting. You want each following car to react less than the previous and have a weaker deceleration/acceleration curve.

Unfortunately, I have noticed increasingly absurd feedback loops in long distance routes here in CA. As a user of conventional cruise control, I can't help but notice how frequently I now have to intervene to adjust speeds in relatively light traffic conditions. On long drives like LA-SF via I-5, these yo-yo drivers are my new nemesis. I don't know if it is due to their use of adaptive cruise controls or a more basic loss of attention or self-awareness. For example, I see packs of cars with speeds oscillating between 55-80 MPH when conditions should easily allow a steady cruise at 75 MPH.

Our two cars both have decent autonomous breaking tech. They did activate in actual risks a couple of times. At least once one prevented a certain crash. They act up rarely. Just some anectodes;

One of them thinks I will drive into a wall when I’m approaching a 90degree turn with a wall. Does the break check from time to time. Nothing weird at high speeds for now.

Other had a single break check at high speed, there was nothing in front so the sensors somehow messed up I guess. It braked for something like 100ms, at least it felt like that. Then kept driving normally. But even that was scary.

> You need to consider that now random new cars may execute a "brake check" maneuver in situations where you would never anticipate a human to have done the same thing.

This is to persuade you to also buy a car with new brake tech ;)

My car does get triggered by lines on the street in a specific area. However, Dutch law says you're supposed to drive at a distance where you can anticipate that the car in front of you can go full stop at any time, so I'm not sure why this should cause people to do that and not the fact that they already should.

> However, Dutch law says you're supposed to drive at a distance where you can anticipate that the car in front of you can go full stop at any time, so I'm not sure why this should cause people to do that and not the fact that they already should.

You've just explained why autonomous braking is completely unnecessary. People are perfect, never make mistakes and never assume that the car in freely-flowing traffic ahead of them won't stamp on the brakes for no apparent reason.

The car will never emergency break as long as you keep your foot on the throttle. My Merc has beeped at me couple times where it thought I was going to collide with something, but because I kept my foot down it didn't actually start breaking - the system only activates if you let go of the gas.

The Subaru actually interprets this as you accelerating into a wall and takes over. You have to let off and then reapply for it to say, “ok, they clearly know something I don’t.”

I just bought a 2018 Subaru Impreza with Eyesight (their suite of ACC, braking, lane assist, etc). I was driving on the freeway into work less than a week after I bought the car and had someone pull out in front of me without signaling or slowing down. The car stopped itself before I had a chance to react and saved me from what could have been a really bad accident.

even warning few seconds before impact is useful, of course there are better systems but Toyota implemented Safety Sense to all cars which is great.

Sorry, but i do not see how the warning is useful, as it first of all distract your attention from driving, and secondly happens too short a time before the would be accident for you to react in my experience. So as a stand alone warning feature without automated breaking, i dont see the use case that you're praising?

A lot of accidents happen because people don't see the car ahead of them.

This could be either because they are distracted (eg. fidgeting with the radio or their mobile phone), or because vision is poor (dense fog).

A system that warns you in those cases that there's a vehicle in front of you sounds useful to me.

This is all too easy. On Friday, I was taking the off-ramp to join a different highway, on cruise control (because I knew the road layout ahead), at the speed limit (70MPH). I glanced down to adjust the heater and when I looked up, a BMW had been sitting on the ghost islands separating the highway and the off-ramp (apparently missed the turn), and the driver had just decided to join the lane I was currently steaming down. Fortunately, the excellent brakes (as well as the loud horn...) in my Supra made up for my lapse in concentration.

I'm in two minds about vehicle automation. Most of it is to compensate for human idiocy (such as the above example). The same gains could be made by humans not doing illegal maneuverers like that. Yes, there are occasions where the electronics can react appropriately to a rapidly developing situation much faster than a human could (e.g. child/animal running into the road), but I agree with the article's caution on complacency. All it needs is for a driver used to auto-braking to get into a car without it and cause an accident, and the technology will suddenly become mandatory.

At the other end of the spectrum, as I've often said, it's technology developed by humans, based on our own understandings, so there will be flaws. Having experienced poor ABS systems that would activate at low speed to the point that I feared the car would not stop at the junction I was approaching, I am not confident auto-brakes will react appropriately in every situation they're called upon.

A lot of vehicular automation is compared to aircraft systems (especially fully autonomous technology) but there is a critical distinction - you never get tailgaters in the air (or if you do, something has gone terribly wrong). Aircraft can rely on huge amounts of automation because in normal use, there are huge amounts of open air in every direction to allow the pilot time to take back control should the systems fail, and still have space and time to correct the immediate problem. Vehicles on the ground are tightly grouped together. Not only does this leave precious little time for humans to react to a bad situation, it also means that any automation systems are similarly constrained. They have to work correctly in a span of seconds or milliseconds. There is no time to 'nope' out and pass control back to the human when they exceed their programming, as is frequently the case with Tesla. Failure is thus very difficult to analyse and account for.

Automation is generally a good thing, but I can't help thinking we might end up automating ourselves into a hole on this one.

Yikes, early ABS brakes were terrifying, especially on snowy or icy roads. I had a couple vehicles that you'd have to start braking a hundred yards earlier than if you were using normal brakes, or else you'd go sailing past where you planned on stopping. Fucking dangerous, if you weren't expecting that behavior.

Another problem with early ABS is that it was widely misunderstood. Many drivers thought it would allow them to stop in a shorter distance under very slippery conditions, when in fact the opposite was often true (but you could steer more effectively). Thus they didn't slow down as much as they should for the conditions and didn't have enough time left to stop.

Also a thick A-pillar will block vision for a few degrees slightly to the sides. Enough to give me a couple of "crap, did not see that (car/pedestrian)" close calls in full daylight.

I feel you there. My partner (who doesn't drive) just bought a second hand Corolla. She'd had it just a few days when I nearly t-boned a flatbed Toyota Hilux because it was hidden completely behind the pillar and just happened to have the correct speed relative to me to allow it to match my turn and remain completely hidden. Luckily, I'm quite cautious at intersections.

I've since learned to move around whenever I'm looking for other vehicles.

Yep, that's a classic case of an engineering trade-off. The thick A-pillars in modern cars are a real detriment to visibility in a place where we need it most, and can not only cause more crashes due to low visibility, but also more impacts with pedestrians since they're frequently hidden in that spot. However, they're also a real boon for crashworthiness: thicker pillars are structurally essential for surviving a rollover accident, and they're also good for holding airbags which can prevent deaths or maimings that the front airbags are insufficient for.

It's a pretty common mistake to rear-end the person in front of you if they stop unexpectedly while you're shoulder-checking for a merge. A warning would probably prevent some of those collisions.

You mean like the mandatory lane change warning light which you should engage much in advance of the manoeuvre already?

Why not do so before the merge check?

I think you're misunderstanding. Consider a merge like the one below. Each line is a lane, and the direction of travel is upwards. This is sometimes how an on-ramp ends, for instance.

     ||
     ||
     ||\A
    C|| \B
     ||  \

Cars A and B are in the \ lane, and Car C is in the leftmost | lane. The \ lane has a yield sign.

The driver in Car A is a new driver, and is uncomfortable merging. The lane they would be entering is clear, but they're spooked by the car in the far lane and stop unnecessarily at the merge point.

The driver in Car B behind them is following closely and is preparing to merge by doing a shoulder check. They are not looking forward when the car in front of them stops. If the way had been blocked they would have been expecting the car ahead to stop, but they had seen it was clear.

The driver of Car B is at-fault in that collision. They were depending on the driver ahead of them to behave predictably, and they were not driving defensively enough. A warning noise would probably have triggered them to slam on the breaks and might have prevented the collision. Automatic emergency breaking would do the same, perhaps more reliably.

(This was a real accident. I was a passenger in the lead car.)

I was always taught (in the UK) to check your mirror before signaling, and then make a final check before the maneuver.

Absolutely disagreed, the car starts beeping if you're approaching a slower car in front of you but don't start slowing down - it has captured my attention more than once on long motorway drives - it does it long enough in advance that you can go "shit I didn't realise we were slowing down".

> as it first of all distract your attention from driving,

They didn't do tests with drivers inexperienced with the system?

I was very happy with the system in my 2014 Cadillac ATS. When paired with the cruise control system, I could set cruise when I got on the highway, and the car would keep distance properly, including coming to a complete stop (and starting up again) for traffic jams.

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