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Comment by AndrewBissell | Hacker News Reader

> It is certainly okay when the rates at which these things happen is lower than the rates at which non-self driving cars have accidents.

Eh, Tesla likes to point to this statistic every time the safety of Autopilot comes into question, but it is an apples-to-oranges comparison because AP is only used on highways where traffic incidents are already far less common per mile driven.

Detailed data is hard to come by, but more nuanced studies have been far from conclusive in favor of the "Autopilot is safer than human drivers" thesis.

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it is an apples-to-oranges comparison because AP is only used on highways where traffic incidents are already far less common per mile driven.

True, and that kind of flawed argument bugs me. However, there is also data that showed that accident rates went down significantly on the same cars after Tesla first enabled autopilot via a software update. This is much more compelling to me; if the same people driving the same cars in the same areas became less likely to get into an accident as soon as autopilot became available, then I don't see how you can really argue that the feature is not beneficial to safety.

This sounds interesting. Are you able to remember where you might have read this?

I assume he's referring to the NHTSA study which was released on the last day of the Obama administration and purported to show a 40% reduction in crash rates. It's still the highest search result on HN for "Tesla Autopilot."

That study was later shown to have employed sketchy data and egregiously flawed methodology. A deeper dive showed that the crash rates may have actually gone up with Autopilot. HN discussion here: https://news.ycombinator.com/item?id=19127613

Thanks for the link. (No idea why your comment has been down voted, certainly wasn't me).

Happens on every Tesla thread.

The way I remember it, Telsa keeps saying something like 'Autopilot is way safer than all-other-road-vehicles-combined'.
What's the point of comparing Telsa Autopilot related crashes to crashes involving at least one motorcycle?

I think it's obvious the answer is: deception*.

That's one possible answer. If they're trying to make their car seem safer than other cars, it's a deceptive statistic to use.

But when the argument is "using the vehicle this way is a lot safer than the minimum requirements to be on the road", it's a relevant and fair statistic.

I'm not convinced that's the right metric though.

A more fair comparison would be: other drivers of similar demography driving other vehicles of similar age and specifications.

Why, though?

I could buy a car with 3 star crash ratings, and people would be fine with that. I could get in a taxi with a mediocre driver, and people would be fine with that.

Why does the comparison have to be to me driving, in a car like this?

When I'm shopping for a car, it makes sense.

But for public policy discussions, what matters is how the safety ranks against the general population.

I get where you’re coming from, and I agree there the needs of public safety policy and self interest don’t always align.

What I mean to say is, when car considering the safety data of any vehicle, it is insufficient to know that the vehicle performs better than whole-fleet.

It’s also necessary to know whether any particular vehicle outperforms others in its class.

One of those without the other is necessary but not sufficient.

More data is almost always better, but I disagree on what's sufficient. If a specific use case ranks moderately high vs. the entire US fleet, then that single piece of data is sufficient.

The driver that's above average but could be more above average isn't where we need to be fixing things. Not when there are millions of drivers that are either hyper-aggressive or senile still on the roads.

Okay, yeah, that’s fair enough.

The question is whether "Autopilot" is safer than "No Autopilot" ceteris paribus, because if it isn't, then a trivial regulation to make the roads safer with zero downside is to just ban Autopilot.

You can't determine whether Autopilot makes driving safer by comparing miles driven only on highways by Teslas to miles driven across the whole vehicle fleet.

> then a trivial regulation to make the roads safer with zero downside is to just ban Autopilot

That assume almost everyone using autopilot will replace that with manual driving in the same car. Some of them might get cheaper cars or take uber and end up less safe.

And even then, there's lots of stuff you can do to a car that makes it less safe that we don't ban, as long as it's still sufficiently safe.

If anything, increase safety standards. If you want to do something that won't cost extra money then do something to ban oversized cars at the same time...

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