Devon TRF Group Forum

Top dressing restores skid resistance, restores a smooth surface (covering any patches) and actually re-waterproofs the road structure. When a road exhibits glassy, bituminous patches, it's called 'fatting up' and becomes extremely slippery, especially in the wet. Chippings on a road surface over time will actually polish up, too, reducing skid resistance.

Spraying on bitumen and covering in fresh chippings is cheaper and as effective as resurfacing......admittedly it's a bit of a hazard for bikes while the chippings are deep, however it's the action of cars etc driving over them for a couple of weeks that helps it all key in properly. 

Grey coloured roads have the highest skid resistance (as the chippings are usually Gritstone - usually high speed roads and in the National Parks), followed by Basalt and the Quartzite (tan coloured , as in East Devon) 

Just sayin'