Top Manufacturers with the Most Number of Miles Traveled per Disengagement in California (2017-18)


California’s Department of Motor Vehicles (DMV) has regularly been at the forefront of maintaining complete transparency in Autonomous Vehicle testing by publishing Disengagement Reports annually. Zimlon accessed these reports (archived by the DMV), to compile a list of reported disengagements among the top AV Manufacturers between September 2017 and November 2018. The DMV requires manufacturers who operate above Level 3 of autonomous driving to submit regular reports regarding the number of disengagements they faced over the year. The DMV defines disengagement as “deactivation of the autonomous mode when a failure of the autonomous technology is detected or when the safe operation of the vehicle requires that the autonomous vehicle test driver disengage the autonomous mode and take immediate manual control of the vehicle.”

The comprehensive list comprises of the total number of miles tested, the number of disengagements and miles per disengagement, reported during this testing. This includes both Driver Initiated and AV initiated disengagements. Miles per Disengagement becomes a very important metric since it helps to discern the amount of traveling an AV has done before it was disengaged by the driver or the AV. This is directly connected to the efficiency of the manufacturer. Though this is the only data regarding disengagements, experts are divided on its benefits.

Experts believe that AV manufacturers have made used of the vague definition of what a disengagement involves, to avoid reporting certain events that could show the technology in poor light. The loophole according to them is the lack of a clear definition of when a driver should take over from the autonomous system. Experts also feel that the lack of information regarding where the testing is being done is another area where these reports fall short. Different terrains and roads have different conditions, which influence the vehicle in multiple ways. Traffic too is an important characteristic, that is missing from these reports. But, manufacturers firmly believe that a decrease in the number of disengagements and an increase in miles traveled is a healthy indicator of improvement in reliability. Inclusion of more characteristics that affect testing, would make the world of Autonomous Vehicles more transparent to its users and would improve the user’s faith in the technology.

Among the 24 manufacturers, Waymo has tested the most number of miles on the roads of California. It reported a mere 114 disengagements in the 926,133.6 miles that it has tested. GM Cruise is not too far behind, with 447,621 miles tested. It faced only 86 disengagements during these tests. Waymo leads the way in efficiency, with 8,123.97 miles traveled per disengagement. GM Cruise is close behind with 5,204.89 miles traveled per disengagement.

In terms of the number of disengagements, Mercedes Benz reported the most number of disengagements, with 1,194 disengagements in the 1749.39 miles that it tested. Auto X has reported over 1,000 disengagements as well. It has had 1,073 disengagements in the 27,442 miles that it has tested.

Transparency through the publishing of these reports keeps concerns about safety at bay.