M5 Bristol tipper truck 'incident'

[530dTPhil]

https://www.itv.com/news/westcountry/2023-03-02/tr...

I am struggling to understand how this can have happened. A tipper truck has either driven along the motorway with its bed raised or the bed has risen whilst the vehicle was in motion.

I believe that the beds are still hydraulically raised but controlled electronically. If this is the case, are there not warnings or safeguards in place to prevent the truck being driven over say 10mph?

Edited by 530dTPhil on Friday 3rd March 16:58