I assume their reasoning would be about grasscutting contractor suing them for damage to his equipment when he is only paid to go in so infrequently due to budget cuts that he might not see even white stones in the overlong grass
Tho since your street hasn't been done in 2 years it may be that the roadsign is so close to a telepole so they don't hit that with the cutter because the verge has overgrown it by then too
I have a narrow strip of hard standing outside my garden wall which isn't wide enough to be a layby but which folk consistently use to take phone calls, sit and row with their passengers over maps and directions, and even put their little boys out to pee against my wall which I find particularly obnoxious
It is also unsettling as a car pulls up and I think for some ridiculous reason that it may be a visitor or someone wanting to speak to me for directions or something, so I am distracted even if I don't go and see. If I do, the folk often glare at me as if I'm interrupting their day rather than the other way around, I've had a few hand signals to that effect and a few that have taken off at speed which might indicate embarrassment of someone canvassing my home for burglary.
I wanted to put topsoil and grass like my neighbour has, but I do find it a useful delivery point and for me to put the car while I close the gate so the hens stay put, tho only one has ever wandered out (twice - and once was despite the closed gate). So I have put my set of 4 wheely bins there to indicate that it isn't a parking spot, tho you'd think the solid white line, the lack of signage and the narrowness for anything bigger than a bicycle would be clues.. And the other side when the outer wall collapsed due to HGV speed over the 30 odd years it's been there, I left it despite offers to charge me to clear up my space and make it look nice for passing drivers again! The rubble will go in a wall foundation when and if I get to the point of redoing it all, and meantime at least it's potentially setting up viability for my gate and wall relocation/rebuild plan I hope..