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Comment by alogray | Hacker News Reader

Has this feature decreased safety? Tesla's first fatality came after 130 million autopilot miles whereas traditions in the US, we have one fatality every 90 million miles. If that continues to hold, this seems to be significantly safer with it's own set of caveats. Not altogether different than getting stuck in a burning car due to your seatbelt.

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I actually worked out the math on this--Tesla is lying with statistics when they made this comment they did about 1 in 130 million miles.

Here's what I did:

  1 in 90 million rate: 1.1 x 10^8
  Probability of No accident in one mile: 1 - 1.1 x 108 = ~9.9999999 x 10^8
  Probability of No accident and driving 130 million miles: (9.99999999 x 10 ^ 8) ^ 130e6 = 0.24
  Probability AT LEAST ONE ACCIDENT in 130 million miles = 1 - 0.24 = 0.76

If you do the same for a rate of 1 in 130 miles you get: 0.63.

So the true rate could really be worse than 1 in 90 million miles and they just got lucky that no incident prevented itself, which would make it more dangerous than a regular car.

Another guy said on divided roads the rate is only about one per 150 million miles [1]

And, that still includes motorcycle accident rates which shouldn't be included in a comparison to Teslas.

[1] https://www.reddit.com/r/technology/comments/4sgxv1/while_te...

In other words, the exact rate is very uncertain when there's only one crash data point. They might be lucky (or unlucky). Well that's obvious, and I wouldn't call it lying at all.

It is misleading though...

I agree that the fatality rate does not allow for any comparisons. Autopilot could cause significantly more or fewer fatalities than humans.

On the other hand, one also needs to consider accident rate. From what I understand, based on US averages, we should have had 50+ accidents out of 100+ million miles driven on AP, but we had about three.

Also, are they counting all previous versions of the software instead of just the latest?

Moreover, I wonder how the human drivers in the statistics fare if you correct for drunk driving / using cellphone, etc. In my opinion, any autopilot worth it's name should be an order of magnitude better than the average human driver.

Averages are a bad way to look at the overall risk.

An example:

  Every time the auto pilot encounters a truck turning in front results in a fatality.
  1 in 10 times a drunk driver fails to avoid the truck turning in time.

The average overall for drunk driver could be 1 in 50 million miles and the auto pilot 1 in 90 million, but you are certain to die in a few instances with the auto pilot, but the human could possibly save himself in the same situation. I imagine the Tesla has lots of these bugs that haven't been found yet.

I would trust a drunk driver over Tesla's autopilot at this point. Don't die for Elon Musk's dream--being one of the first auto pilot fatalities isn't that big of an accomplishment.

Also, I'd give "Technopoly" a read.

That's 90 million miles among all cars.

I'd wager that if you compare it with cars at Tesla price point -- mostly luxury cars -- Tesla would look pretty bad.

Why do you think the accident rate is lower among luxury cars as compared to more common vehicles? I would suspect the opposite. My hypothesis is that the people who seek out and buy cars that go 0 to 60 in 3.2 seconds probably drive faster and more aggressively than average. They therefore are more likely to have an accident.

> My hypothesis is that the people who seek out and buy cars that go 0 to 60 in 3.2 seconds probably drive faster and more aggressively than average

Highly unscientific anecdotal evidence and personal experience living in an area with an unusually high concentration of such cars shows me that most people that own really fast cars do drive fast and enthusiastically from time to time but do so in a responsible manner and typically respectfully go with the flow, whereas a lot of people with more regular cars (mostly MPVs around here) have a habit of driving a good deal too close and a good deal too fast every single day. Many even engage in some truly reckless behaviour as soon as they feel threatened/frustrated, a telltale sign of power/control issues.

Very anecdotal evidence here commuting in Toronto here: - more drivers in $80k+ cars leave 2-3 times the following distance than other drivers with cheaper cars. Not all, but very noticeable sometimes.

Several reasons, but again, it is just guessing that cannot replace actual data. That doesn't mean we should take the only data point available (90 million miles) and declare it settled.

Your point about people seeking to drive faster is a valid one.

The counterpoint is there are people who cannot afford luxury cars but also want to drive faster -- they'll end up buying cheaper cars that can drive fast within their price range. Those are likely to be more fatal than the average luxury car.

1) Hypothesis on car age. An accident on a 2002 non-luxury car model is supposedly more likely to be fatal than an accident with your average new car.

This matters because Teslas with autopilot are relatively new compared to overall car population.

2) Hypothesis that low cost cars are more fatal than an average luxury cars.

3) Demographic hypothesis. Because of price point, the buyer demographic of newer luxury cars will be different than the overall demographic. Age group (e.g. teenagers vs. young adults vs. older adults), education level, profession.

Luxury cars do tend to do pretty well among late model cars in terms of fatality rates--haven't seen rates for accidents overall. But the biggest correlation is probably that bigger cars are safer and smaller cars less so:

http://www.cbsnews.com/news/report-lists-cars-with-highest-a...

The fatality rates are probably also notably better on late model cars relative to clunkers because of safety features.

But this is overanalyzing, if we use only the "1 fatality in 130 million miles" stat. That 1 fatality was a car driving under a truck at speed and losing its entire top half.

I don't think more expensive cars are less likely to have that kind of accident, nor would it be less fatal.

I was responding to a specific comment. I agree that fatality statistics are utterly meaningless based on one event.

Most of them have a lot of safety features, like automatically braking if needed.

Really? Bringing guesses to a fact game. We can do better.

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