The National Transportation Safety Board (US) has released a summary of a workshop that it held in 2016 on the issue of rear seat safety. The workshop addresses a number of issues related to carseat/booster fit, as well as more general issues related to safety of rear seat occupants. As has been discussed here in various threads, there is some concern that advances in safety have primarily focused on front seat passengers, and that adapting them to the rear seat involves additional challenges. Adult passengers in the rear seat also tend to have lower seatbelt usage rates, leading to greater injury severity, and the NTSB document discusses some approaches including reminder systems.
Link to NTSB:
https://www.ntsb.gov/news/events/Documents/2016_rss_WS_Summary.pdf
Link to NTSB:
https://www.ntsb.gov/news/events/Documents/2016_rss_WS_Summary.pdf