I think it possibly all boils down to our built-in instincts. We have evolved to be on the lookout for things which constitute a personal danger. (Those people who don't/can't are quickly allocated to the Darwin Awards competition.)
As a driver, a huge 20-ton truck is a very noticeable personal danger. Once seen, you make sure that you know where it is at all times when you're near enough to be 'damaged' by it.
On the other hand, a cyclist/motorcyclist, even when seen, is assessed as a 'negative danger'. That is, the cyclist is more at risk from you, rather than you from him, whether or not a collision actually occurs.
This means that a cyclist can be disregarded as a danger threat, and may be 'blocked out' to some extent. The amount of blocking out, I would expect, is a function of gradation amongst other present threats. In other words, if a huge truck is present, you're more likely to 'unsee' the cyclist.
This all happens subconsciously, and is just part of our evolution over millions of years as a species. As such, it probably means that we need to find ways to produce an 'un-natural' outcome rather than the current 'natural' situation..
As a driver, a huge 20-ton truck is a very noticeable personal danger. Once seen, you make sure that you know where it is at all times when you're near enough to be 'damaged' by it.
On the other hand, a cyclist/motorcyclist, even when seen, is assessed as a 'negative danger'. That is, the cyclist is more at risk from you, rather than you from him, whether or not a collision actually occurs.
This means that a cyclist can be disregarded as a danger threat, and may be 'blocked out' to some extent. The amount of blocking out, I would expect, is a function of gradation amongst other present threats. In other words, if a huge truck is present, you're more likely to 'unsee' the cyclist.
This all happens subconsciously, and is just part of our evolution over millions of years as a species. As such, it probably means that we need to find ways to produce an 'un-natural' outcome rather than the current 'natural' situation..