I don't think it's that people don't notice or see, it's that the recognition is mostly subconcious. I was once driving on a 3 lane highway with a semi going s

I don't think it's that people don't notice or see, it's that the recognition is mostly subconcious. I was once driving on a 3 lane highway with a semi going slowly in the middle lane. I was in the left lane and passed him but needed the right lane for an upcoming exit. I pass the semi, slide into the middle lane and then wait. I realized I was waiting on a small blue car that, sure enough, popped out of the right lane going faster than either one of us. And I realized I had processed that a small blue car was also passing the semi going faster than either the semi or myself and that I needed to wait for them before completing my move into the far right lane. I think often times things get processed at a subconcious level and I imagine that's what was happening with the anecdote about arrows.