Underlying study is here. [1] Full disclosure, I co-wrote the piece for The Daily Beast [2] that originally suggested that Tesla's methodology was seriously flawed. I am not a Tesla-hater though — I just thought it was odd that the company was playing quite so fast and loose with their safety claims.
1: https://engrxiv.org/preprint/view/1973/3986
2: https://www.thedailybeast.com/how-tesla-and-elon-musk-exagge...