>> We'd never release any product with ridiculous standards like "Test for 100 years".

The same timeframe does not necessarily apply to other kinds of systems. The study is about self-driving cars and the numbers quoted are about self-driving cars, in particular self-driving cars compared to human-driven cars.

The study starts by defining various industry-standard measures of reliability, for example scroll down to page 3 and look at equation 1 and equation 2. You can see that those are not about "perfect safety" but about measuring the probability of an accident and so on.

As a general rule, if you are confused by the text of a study, check out the maths. They should be unambiguous.

Sure, but the conclusion of the post was something like "we can't test these things enough". Which seems like a deliberate misrepresentation of the math as well.

I'm sorry, which post do you mean? Who said 'something like "we can't test these things enough"'?

Original horseless carriages had enough weird rules: https://en.m.wikipedia.org/wiki/Locomotive_Acts

Edit: it took almost 4 decades to improve them. We are starting with driverless vehicles just right now.