From my discussions with a friend with intimate knowledge of the software side of Cruise, there is wild skepticism within the co that they even have the hardware needed to go L4 or L5. Big promises being made to GM by Kyle which is leading to smoke and mirrors to distract/buy time from more critical problems "under the hood."
( here is the 2016 report: https://www.dmv.ca.gov/portal/wcm/connect/deade5b7-5b10-4b25... , found here: https://www.dmv.ca.gov/portal/dmv/detail/vr/autonomous/disen... )