Waymo, Google’s self-driving unit, has claimed a critical key metric in measuring the success of self-driving performance, citing the least human interventions required by its cars on public streets.

According to a California Department of Motor Vehicles report, Waymo’s fleet of self-driving Chrysler Pacific hybrid minivans has logged the most average miles driven without “disengagement” from Dec. 2016 through Nov. 2017, clocking 5,596 miles. The official meaning of the term relates to any self-driving system kicking off control from system to human due to system failure or other scenario requiring human input, a measure of the system’s own “reliability.’

Coming in second and third place, respectively, was General Motors’ Cruise, with 1,214 miles on average in between disengagements, and Nissan’s vehicles with 208 miles on average. In totals, Waymo’s Pacificas drove 352,545 miles in the state during the test period, with 63 total disengagements compared to the Cruise’s 127,516 miles driven, with 105 disengagements. Other automakers cited in the report include Mercedes, Ford, Honda, BMW, Volkswagen, Tesla, and nVidia.

To date, Waymo has made several achievements during its testing phase, claiming more than four million real-world autonomous miles and 20,000-plus completed tested scenarios using private test tracks and simulators. On the beta side, Waymo also launched an “early rider program” which let select participants download and hail cars using a smartphone app within a 100-square-mile radius area in Phoenix Arizona, free of charge.

This week, Waymo has also obtained approval from the state of Ariz. to launch its ride-hailing services, successfully acquiring its first TNC permit.