On the road between Phusing & Bauchet, there are white numbers painted randomly on the road, and each one marked with a pink ribbon. All the numbers seem to be between 400 and 600, and are not at all evenly spaced. A couple are even by the edge of the road. Does anyone know what this signifies? My guess, as the road is in dire need of repair, that this tells the repair crew the depth of the tarmac.

On the road between Phusing & Bauchet, there are white numbers painted randomly on the road, and each one marked with a pink ribbon. All the numbers seem to be between 400 and 600, and are not at all evenly spaced. A couple are even by the edge of the road. Does anyone know what this signifies? My guess, as the road is in dire need of repair, that this tells the repair crew the depth of the tarmac.

At a guess I would say it's the elevation. When the road is repaired they are probably going to super-elevate the corners so your car remains level when you go round at high speed.

600 is far too thick for the depth of tarmac here even in millimetres. That's why roads need repairng every six months or even sooner.