Disengagements-per-mile. No, this has nothing to do with couples breaking off their wedding while driving, but everything to do with self-driving (autonomous) vehicles.
Every year California, where many autonomous vehicle projects are headquartered, requires that all companies testing autonomous vehicles in the state file a "disengagement report" which measures how many times a human driver had to intervene and take control of an autonomous vehicle.
On this one simple metric Waymo, the self-driving car division of Google's parent company, and Cruise (owned by General Motors), are way out in front of everyone else — with both of their fleets averaging almost 30,000 miles driven for each human disengagement.
The fact that autonomous vehicles can drive for almost 30,000 miles before a human needs to intervene is pretty astonishing, even if you account for the fact that those miles may have been driven on very simple roads or highways with limited traffic.
Is this a good measure?
Experts in the industry often downplay the importance of disengagements-per-mile as a measuring stick, for a number of reasons. One is that it is possible to do a bunch of easy miles in California, and do more complicated testing elsewhere, to make your numbers look good. The reports also offer a lot of leeway on how each company defines a "disengagement" — and under what conditions they test. Nevertheless, because most of these companies are incredibly secretive about their progress it's about as good a comparison as we have at the moment.
Even taking the numbers with a pinch of salt, it's interesting to see how many of the big companies — including Apple — are quite far behind. Apple's data revealed that their autonomous fleet racked up 18,800 miles in California, with 130 disengagements. That's about one intervention every 144 miles — way off the pace set by Waymo and Cruise.
