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Comment by nmca | Hacker News Reader

This paper consistently assumes a fleet size of 100, and 24/7/365 driving. These are silly in different directions, but I think the former invalidates a lot of their claims. As a slightly not-random example, GM produces around 30,000 Chevy Bolts a year. Things start to look a little expensive, but the paper claims "This analysis shows that for fatalities it is not possible to test-drive autonomous vehicles to demonstrate their safety to any plausible standard". I think they are neglecting "without increasing fleet sizes beyond 100 vehicles".

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Their assumptions are just one way of reaching the 275 million mile mark needed to hit that 95% confidence interval. If we're looking at actual numbers, Waymo's recently boasted of hitting the 7 million mile mark over several years of testing so if anything, Rand's assumption of 275M miles in 12.5 years for a test programme looks to be erring on the generous side. Sure, if Chevrolet decided to use their entire production run of Bolts to test autonomous vehicle performance you'd get 275 million miles pretty quickly, but they might struggle to get consumer buy in and regulator approval for selling fully autonomous driving capability to 30,000 consumers unless and until they can produce evidence that their autonomous mode accident rate is lower than human drivers...

And there's a much bigger problem, in that the software being tested is continually evolving, and modifications which result in improvement in general driving conditions don't necessarily tends towards stable (or monotonically reducing) numbers of rare accident-inducing bugs.

Ah, and indeed it seems like substantial (>10x) fleet size increases are planned.

https://www.theverge.com/2018/1/30/16948356/waymo-google-fia...

FWIW the paper mentions that Google's autonomous driving fleet currently has 55 cars, so I suspect the 100 fleet size was picked to reflect a significant improvement over a notable competitor in the field.

The article mentions Google's self-driving fleet size but I didn't notice other companies. I wonder what the fleet size is at other companies that are working on this, anyone know?

The reason I ask is that I'm curious if "making more cars" is really the bottleneck. It's totally possible that the Waymo team doesn't have the headcount to keep up with the data output from the existing 55 units, or the fleet logistics bandwidth to keep up more than 50 or 60 heavily custom self-driving vehicles. It may very reasonably be a staffing issue rather than a money one, and it's possible that even if Google bought the rest of the self driving industry they might not be able to maintain more than a couple hundred cars.

Disclaimer: I work for Google, but not on self driving cars. I actually know almost nothing about our self driving efforts, sorry.

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