Comment by mbreese
2 hours ago
The more I think about your comment on statistics, the more I change my mind.
At first, I think you’re right - these are (thankfully) rare events. And because of this, the accident rate is Poisson distributed. At this low of a rate, it’s really hard to know what the true average is, so we do really need more time/miles to know how good/bad the Teslas are performing. I also suspect they are getting safer over time, but again… more data required. But, we do have the statistical models to work with these rare events.
But then I think about your comment about it only being 30 cars operating over 6 months. Which, makes sense, except for the fact that it’s not like having a fleet of individual drivers. These robotaxis should all be running the same software, so it’s statistically more like one person driving 500,000 miles. This is a lot of miles! I’ve been driving for over 30 years and I don’t think I’ve driven that many miles. This should be enough data for a comparison.
If we are comparing the Tesla accident rate to people in a consistent manner (accident classification), it’s a valid comparison. So, I think the way this works out is: given an accident rate of 1/500000, we could expect a human to have 9 accidents over the same miles with a probability of ~ 1 x 10^-6. (Never do live math on the internet, but I think this is about right).
Hopefully they will get better.
500,000 / 30 years is ~16,667mi/yr. While its a bit above the US average, its not incredibly so. Tons of normal commuters will have driven more than that many miles in 30 years.
That’s not the point (I’m a bit of an outlier, I don’t drive much daily, but make long trips fairly often). The point with focusing on 500,000 miles is that that should be enough of an observation period to be able to make some comparisons. The parent comment was making it seem like that was too low. Putting it into context of how much I’ve driven makes me think that 500,000 miles is enough to make a valid comparison.