The grit is for ICE not snow the reason for the vast spread SurreyGuy is the Spreader at the rear of the Gritting Lorry that's how it's designed, regards screen damage, this will not happen, the skid is caused by cars' HGVs aquaplaning ( Tyres not in contact with the road surface) it does not make any difference if you are carrying 44 tons & there is Ice about the Truck will aquaplane, What used to pis me off on the Motorways which I used to use a lot why when it's snowing hard why the police do not allow the HGVs to use the outside lane to keep the motorway clear, as soon as the private Motorist see the snow in the outside lane they get the Mangetouts then all stop in the Middle In-turn the outside lane becoming closed. Bit of advise if I may, Do not think you can be smarter than Ice, I have seen people try, a clue to Ice, VERY VERY LIGHT STEERING, At night when there is Black Ice about look for a sparkling of the road surface, am I being a clever sod!! NO, HGV experience has taught me that. I am trying to pass it on. Safe Journey all.