If someone wants to know more about why such a situation would eventually result in a collision, look for the term "Constant bearing, decreasing range", e.g. in Wikipedia:
https://en.wikipedia.org/wiki/Constant_bearing,_decreasing_r...
https://en.wikipedia.org/wiki/Constant_bearing,_decreasing_r...
I would have to fight my instinct to swerve away and consciously reassure myself that it was just the sign that I saw.