It's not just the motorway. I remember commuting from Spalding to Peterborough on what the press called a 'killer road'. Several people had high speed accidents and landed upside down in fields because it was long and straight, but the surface wasn't as flat as it looked, due to the fen beneath having an awkward habit of moving.
Perfectly safe to travel at around the speed limit, but a perfect take-off ramp in places if travelling too fast.
One of the rozzers that used to be on C5s Police Interceptors before IIRC medically retiring with PTSD now has a YouTube channel I was watching only yesterday. Same as your last paragraph, some fella was going just a little too fast and misjudged a blind crest that had a slight bend on it as well as a slight adverse camber. Due to the road ‘falling away’ after the peak of the crest with the added complexity of the bend and the camber he’d shot straight off the roadside and had been killed by a tree branch, Final Destination style by the sounds of it.
One of the first paramedics on scene later quit the service as a result. I don’t know how so many first responders make a career out of it.