I use wet and dry paper glued down with a cardboard rib in the middle to give a camber. No painting or added surfacing needed, just look for the right grade and colour to suit the specific location. Cut slightly oversize and Metcalfe pavements sit on top to give a nice kerb effect. Adhesive address labels cut in strips make white lines and pedestrian crossings etc. and although I have never tried it could conceivably be painted yellow before cutting to give those pretty yellow lines that the councils like to decorate the roads with.