Good question Ian, I’m not really sure how my setup would fare in a serious accident, but it feels sturdy and secure and I would expect a relatively minor accident wouldn’t do any harm, but in a serious collision then it could fail, it hasn’t been crash tested after all.
The forks are secured using their through axles/quick releases and those brackets are bolted/screwed through 18mm ply. I intend to add some strapping points to secure the rear wheels. The whole unit is very sturdy and bolted to the existing lashing points using M10 bolts. I think it would need a pretty significant impact to cause a failure and present any danger to the bikes or passengers.