Horrific and tragic. Potentially an understatement, but I can't think of the right words to use in this instance.
I'm not going to get into the blame game as there are too many questions for other people to consider first, but regardless of who ends up being at fault here, at what point does someone turn around and say we need to review the rules of the road re: cycling allowance on such highways?
I get what people have said about weighing up the risks on an personal basis, but truly its not fair when people don't/can't understand the individual risks. Motorways are motorways, everyone knows what to expect, and that bikes shouldn't be on them; everyone's happy.
IMO, the A-Road classification (and the subsequent allowance of cycling transit upon them) in this regards is far too broad. A Roads can be anything from pseudo-motorways to gridlocked, single-lane moving car parks in town centres. Ok, people can prepare to a degree by pre-investigating them, but you will never truly know the nature of a road until you've cycled it, sometimes to a very high cost. Locals would know to give it a wide birth, "foreigners" may well think its a risk worth taking through lack of experience.
I know it may be a dubious subject, but I believe roads like this stretch need some kind of re-categorization and subsequent banning of bikes. Whether we like it or not, this kind of road was designed for the fast transit of heavy transport, the fact that we are allowed upon them is a technicality and an oversight. To simply say lorry drivers need training or some such thing is too simplistic.
I've been measuring up a direct JOGLE route, and the A30 was very much in consideration. I'm now having a serious rethink.