In the UK the only contaminated runway condition that can be measured for grip and reported is compacted snow or ice. Thats why you have snow and ice tables in the cockpit.
UK aerodromes always shut for runway sweeping and reopen once blacktop is achieved. There might be remnants of some slushy snow in traces but it's this condition for which the UK do not permit the use of the friction cart.
Sir George Cayley