The debate is taking on more importance amid delays in the rollout of self-driving vehicles and concerns over a lack of regulation and the prospects for profitability for the companies that make such vehicles.
The focus on disengagements -- when a human driver must take manual control from a self-driving system -- and the backlash from self-driving companies have been growing since the California Department of Motor Vehicles began releasing annual disengagement reports five years ago.
In a February 2019 blog post, Waymo wrote that "the key to self-driving technology safely improving and scaling is through a robust breadth of experience and scenario testing, represented by a wider array of data points beyond disengagement alone."
Self-driving companies say the disengagement data can draw unfair comparisons between companies and their self-driving technology.
Aurora co-founder Chris Urmson, who previously headed Waymo's self-driving program, wrote last month that "these numbers mean little when there's no clear definition of what constitutes a disengagement."
Cruise co-founder Kyle Vogt expressed similar concerns in a blog post last month, adding: