You've only just spotted them? They've been there for (literally) decades. AFAIK they are markers for VASCAR, and for helicopters to estimate speeds (ASIs aren't much use for getting vehicle speeds)....
I'm sure many of you will have seen some small white box markings painted on the carriageway approximately 300 x 300 mm and spaced well apart - maybe a mile or more.
Raising money for cancer research
Hello all
Having been touched in my life by cancer too many time than I want to remember, I made up