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Comment by bryanlarsen | Hacker News Reader

There's another article prominently linked from the OP titled '5 Things that Give Self-Driving Cars Headaches". The trolley problem is #5, and it's described as having 'no solution', yet it has the simplest solution: slow down.

If you're ever in a situation where it's possible for a child to jump in front of your car and you are not able to stop in less than a car length or at most two, you were driving too fast. And if you're driving slow enough to stop that quickly, it doesn't matter what the car does, it's not going to kill anybody.

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Agree. Rule #1 for a car, human or machine driven, is don't drive faster than your brakes can stop you, in the distance you can see. A machine that could do this would be better than 90% of people, IMHO. Doing this makes toy ethics problems irrelevant.

A machine can already do the act of stopping better than 100% of the people.

The problem is recognizing the obstacle with a better accuracy than people do. Tesla's a good example for this, and being unable to recognize certain obstacles in certain conditions.

This is an extreme case, but if the policy is to slow down and/or stop, then that can be manipulated. Imagine your car takes you through a bad part of town and a group of people want to rob you -- they just have to stand in the car's path and it will stop.

It feels weird saying this, but there is a sort of physical threat that being behind the wheel gives you.

That's not weird. As a driver of a car, you control much more destructive and lethal potential than someone with a 9mm handgun. (You can even quantify that in terms of kinetic energy.)

In certain places (big cities in Brazil come to mind, maybe even some places in the US?) it is customary to ignore certain red traffic lights at night because stopping there is very likely to get you carjacked. I'd like to see the autonomous car that can do that correctly and safely.

Same goes for when the lights at a junction are out of service. How will an AI handle that?

In general, proper autonomous cars are going to need a shit-ton of data collection at a very fine level everywhere. Together with the required sensor suite, the cost increase over a normal car in the same class is going to be huge. I'm not talking 20%, I'm talking at least twice as expensive.

This is why I think Ford are making exactly the right bet: taxi companies will adopt driverless cars many years, even decades, before private drivers. Because a taxi company saves a lot of money on not having any drivers (I'm guessing not far from 100-150k per year per car) on an autonomous car, they could easily afford to pay $150k for a Ford Fusion (normally $30k).

Except that children can jump in front of you at arbitrary close distances so it's not possible to satisfy that.

This purported solution seems to be a special case of "assume I will never encounter a moral dilemma that forces me to make a hard choice". It's not solving the dilemma, but refusing to recognize that one exists. [1] Even if you think it can't happen this way, there are a hundred other ways it can manifest while driving.

[1] LessWrongers advocate the practice of choosing the "least convenient possible world" to avoid such side-stepping: https://wiki.lesswrong.com/wiki/Least_convenient_possible_wo...

The trolley problem obtains its ethical considerations from the lethal outcomes. When you are driving you can easily prevent a lethal outcome by slowing down. Even a child is unlikely to die when struck by a car going 20 MPH or less. So yes, slowing down does fix this problem. If you are driving down a street where it is possible that a child will suddenly leap out, completely unseen by you, then you should be driving 20 MPH at most.

So you should always drive at less than 20mph?

For every "but that'll never happen" there's a contrived scenario where it could. Yes, it could be a vanishingly small chance, but it's not going to go away.

Everywhere? No but in neighborhoods with limited sight lines I do. You ever heard of the 20's Plenty campaign?

Indeed (we've something similar here in the UK).

The point I was trying to make is that the trolley problem is always going to exist, saying "no, just slow down" doesn't make the problem of making decisions go away.

There are always going to be scenarios where an automated system is going to have to decide what to do in a life or death situation. And someone's going to have to decide how such systems will respond.

I don't see how they could do a worse job than the humans do. Most human drivers aren't aware of the life-or-death situation until a loud noise interrupts their snapchatting.

Trolley situations require approximately equal chances of death for passengers and pedestrians. Nobody or nothing can predict such probabilities with any degree of accuracy. Some people die when they trip and fall, others survive 80mph collisions.

So either the situation has obvious probabilities and subsequently obvious solutions or there are such huge error bars that there's no right answer.

So you divide into two categories:

- stuff that is relatively common, like children playing on streets. So if you get into that situation you were driving too fast, or there's something you should have done in the first place to avoid it.

- stuff that isn't common, like children playing on freeways. In which case it's rare enough that the answer is a nice philosophical exercise but isn't practical. The real world is never as clean as such philosophical exercises. Defaulting to 'slam on the brakes' may perhaps be improved upon, but the difference will be very marginal.

The way the question is presented, at least in the MIT examples and Trolley problem, dictates that slowing down isn't an option. Probably due to catastrophic brake failure or something similar

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