Gritting
What is gritting?
Despite the name, gritting rarely involves grit (a mix of sand and stones) at all. Gritting involves spreading rock salt onto roads and pavements to prevent ice forming or to help melt snow and ice.
In Derby, we grit roads using rock salt which has been coated in molasses. The molasses helps the salt to dissolve quicker and stick better to the road surface, making it more effective than uncoated salt.
When the salt dissolves in surface water (helped by vehicle and foot traffic to crush it) it lowers the freezing temperature of the water. Instead of freezing at 0° any moisture freezes at -6° to -8°.