I stopped for a moment to take this picture of a rather decrepit-looking cats-eye road-stud:
(click the image for the huge original picture)
The whole is is only about half a foot wide, I photographed it in macro-mode to bring out the detail in the decaying rubber.
That road is a little-used dead-end in Dundee, only used by the two adjacent houses and by learner drivers attempting three-point-turns.
I think that this bit of road used to be part of a main road, superceded and cut off by more recent road-building nearby.
That would explain the unnecessary (and unmaintained) road-markings.
(a healthy cats-eye should look more like the one here, this one's missing its "eyes")