Not an excuse, but a possible explanation for those who wonder, "how could this happen".
There's a thing called "
target fixation" whereby we fixate on things and end up running into what we're trying to avoid. Possible it's an acquired instinct left over from our past lives as an apex predator. This may be why drivers crash into things on shoulders that they couldn't not see, including tractor trailers, emergency vehicles, police cars with strobes flashing, and, unfortunately, cyclists.
There's things we can do to overcome target fixation, like training ourselves to focus where we want to go (escape path) rather than the hazard we want to avoid, but that won't help when the it's the driver behind us fixating.
Target fixation is one reason I avoid riding on shoulders or even the right edge. By riding in the lane, I'm in the driver's central zone of vision, and my lateral movement to the right as he approaches helps break the fixation, which (hopefully) stays locked in the place I was.