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Comment by twobitshifter | Hacker News Reader

This isn’t really a new problem. You could engine brake your manual transmission car without touching the brakes and there’s such a thing as going uphill. I think the bolt solution of an accelerometer gives the best indication that a car is slowing down quickly.

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It's a US problem probably, everywhere manual transmission was or is a thing everybody expects cars to slow down. Also: keep enough distance, pay attention and this is never an issue.

Well yes, but engine breaking is a lot weaker then regen braking can be, so there really needs to be break lights id deceleration is more than one would reasonably expect engine breaking to achieve

Really depends on the car. There are cars with very little inertia, if you let go of the gas pedal quickly they will get quite jerky. In those, you really have to depress the clutch before completely letting go of the accelerator.

What kind of a car is that? I have 1.6l hyndai ix20 and I can let off gas at any time with zero issues....

> keep enough distance, pay attention and this is never an issue

If this was helpful, far fewer crashes would happen on roads today. People are imperfect. They're distracted, they have slow reaction times, they have poor vision, and they drive in poor weather.

As the video states, regulations should definitely be altered to require car manufacturers to show brake lights no matter how deceleration occurs. It's just one additional way to prevent collisions.

> keep enough distance, pay attention and this is never an issue

That isn’t how safety regulations work. Driving is a cooperative affair and giving more information about your intend to the drivers around you is a good thing.

I mean if all it took was “keep distance and pay attention” why bother with turn signals?

And as a side note: “self driving” cars still haven’t completely figured out the right algorithm for turn signals. I watch enough “AI Driver” on YouTube to see him call out how Tesla’s turn signaling is sometimes pretty erratic. It is probably a pretty hard problem when you think about it.

Showing brake lights is much easier. Got a deceleration over a certain value? Well, show them lights!

> I mean if all it took was “keep distance and pay attention” why bother with turn signals?

Have you met BMW drivers? /s

You should be practicing defensive driving whenever you drive. It's what's taught nowadays and has been for a long while.

You should expect others to be driving at their worst. No turn signals, broken tail lights, erratic lane change, abrupt braking or acceleration, the whole shebang. Expecting the worst is the best way to ensure your own safety on the road.

I laughed at the mention of BMW drivers because it's so spot on. I agree that defensive driving is always the way to go, but at a certain point you need information. TC essentially goes from 100km/h to stopped in less than 15 seconds without any obvious visual indication. That's coming to the point where there's almost no defensive driving possible and a deadly highway collision becomes more likely than not.

It's the same in any situation. Always assume people will do completely insane things and prepare accordingly, but that doesn't mean we should make things more dangerous for no good reason. For all the truth that more chaotic roads make for more attentive drivers, they also still make for more accidents.

Yes. But the point is more information is good. You can be the most observant most defensively best trained driver, and more predictable information is still good.

I don't understand the motivation of arguing an objectively provably demonstrably good thing, because some other thing is also good :-).

Sure, more information is good, but you shouldn't expect that information. People don't use DRLs and turn signals all the time. Lights break. Electrical connections degrade. Old cars almost never keep up with advancements in signaling technology.

All the signals in the world wouldn't help people deal with someone that refuses to use their indicators or doesn't maintain their old car, and that is the expectation you should have when driving: the worst possible drivers around you all the time.

You can deal with practically any situation as long as you're keeping your distance and staying observant. Regardless what the people around you are or are not doing.

Agreed. Fully.

And yet precisely none of that, to me at least, is persuasive reason to NOT put the most effective possible light and information on cars coming out of the factory :-)

(And don't even get me started on red vs amber rear turning signals ;)

There are two different problems.

One is educating drivers to be better. Drive more predictably, drive more defensively, drive safer in adverse conditions, etc.

The other is designing the driving experience as a system to deal with humans. Systems that don't anticipate human faults are brittle and, frankly, shitty. Just like you can't expect 100% of users to be phish resistant, you can _not_ expect perfection from drivers, and you _must_ build in compensations to deal with it. That means well designed roads, good brakes lights, and even brake lights that account for one-pedal driving.

Adding new indicators is an obvious and inoffensive thing to do. I don't think anyone is claiming we shouldn't build cars to be safe.

It is, however, horrifying that there are drivers so incompetent they don't even know what engine braking is. It is hardly an advanced topic. Any driver who doesn't know cars can decelerate without the brake lights coming on has no business being on the road.

In my neck of the woods at least, driving safely is impossible. Nearly every major road is over capacity and getting worse. Most drivers are half-trained at best. Constant traffic jams fray the nerves. A lack of public transportation means people are on the road for longer than they can focus. The best selling vehicle is the Ford F-150. Leaving adequate following distance just results in someone taking that as an invitation to swerve a quarter second in front of you.

We should develop every technical solution we can, but the reason American drivers are in so much danger is social.

Keep enoug distance to be safe and someone will just change a lane to be in front of you, removing any safe distance you decided to keep

Then slow down a bit and make more space. Traffic flows better when people have room to change lanes.

That's my complaint, if I do someone just fills that space because their lane is going 2cm/minute slower than mine

Then slow down a bit and make more space. There's no trophy at the end.

Which causes next car to get in front. Still no space, nor more safety, and also triggering morons to do extra maneuvers and potentially fuck up more.

Do you lack ability to think about the results of the actions ?

Going uphill isnt a problem because the car behind you is also going uphill. The point of brake lights is to warn driver's behind you they need to brake, which is why it needs to be a measure of negative force being applied by the car, not just the resultant acceleration vector.

I've thought about putting a manual brake light switch in my manual transmission car because of this, but I'm also that guy that engine brakes more than actual brakes. 6 years of owning this car and I've never worn out a brake pad.

Wouldn't it be easier to just put some light pressure on your break pedal while you're engine breaking? My older Acura definitely lights up the break lights well before actually engaging the brakes.

Much easier, but not as technically interesting :) And I do pedal it if I think the driver behind me is risky, though I'm not sure where the light engagement is relative to brake engagement.

That foot is on the gas pedal still in a lot of cases

It's so nice to not have to ride your brakes going downhill, especially when you also have to turn at the same time. (I miss my old manual car)

Newer manuals are really nice.. mine has hill hold, which some people hate but I enjoy. And supposedly engine braking uses no fuel.

Unless you have an older carbureted vehicle, engine braking should use no fuel:

https://en.wikipedia.org/wiki/Engine_braking#Limitations

Just do a decent job matching revs on the downshifts so you don't trade brake dust for clutch dust :)

Not all hill holds are created equal. On my car, the brakes release as soon as you start moving forward after hill hold, or after 1.8 seconds. On my friend's subaru, the brakes hold for 2 seconds period. That means if you can do a hill start in less than 2 seconds, you drag the brakes every time.

15 civic SI. Hill hold is 1.2 seconds I think and no early disengagement. But it's rear brakes only. You can't disable it that I know of.

Why would you need an accelerometer when you've got perfectly good tacho pulses from the ABS rings?

AFAIK ABS modules already have accelerometers. If I had to guess it falls into the domain of the ABS module, and it's just easier to talk about it as an accelerometer, when it's really using multiple inputs (wheel speed sensors can fail).

I hope whatever new regulation is intelligent enough to not consider the deceleration from coasting up a hill to be part of triggering the brake lights. Brake lights should only come on when there is deceleration beyond what you'd expect from a naturally rolling car.

One would assume it's not a difficult process to model.

If the driver presses the brake, put the brake lights on.

If the driver lifts off the throttle in heavy regen mode and the vehicle slows faster than <some amount> put the brake light on.

If the vehicle slows faster than <some amount> with the throttle "off idle", do not put the brake light on.

In theory you can, but 99% of the time you'd still generally use the brakes for any serious deceleration. On the other hand with one pedal driving, regen braking is used 99% of the time.

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