slight correction too that I believe (happy to be proven wrong) that Southern 171s is driver release guard close.
I think as thing move forward there will be a push for “Driver controlled operation” where there is a SC guard on every train that can do the doors if required, but normally the driver will have full control of the doors. I can’t see a push for future expansion of pure DOO, and I’m not convinced on the OBS position (however GTR / DfT have proven a lot of people wrong, many assumed that the grade would be binned off ASAP. 8 years later and they’re still actively recruiting the role).
I personally believe that driver release, guard close is better, however only if the ASDO system can detect and prevent a station stop short, however as mentioned above, many ASDO systems just release x number of coaches regardless of where the train stops.
Final point from me, the reduction in PTI incidents after LO moved to DOO. Surely that’s because there are no more ready to start against the red? I would very much imagine there’s been an increase in other incidents such as trap and drags, and other station irregularities. It would be interesting to know more granular details as to what has increased / decreased as a result of moving to full DOO.