Once the gritter has put salt on the road all ice will melt.
This is not true! Spreading salt on the road is only the start of the de-icing process. Movement of salt around the road by traffic is essential to complete the process. Overnight, when traffic levels are low, roads can remain icy for some time.
Spreading salt on fresh snow will melt it more quickly.
This is not true! Salt only effectively melts snow when it is less than 40mm deep and traffic can move the salt around. It is essential we plough fresh snow to a depth of 40mm before spreading salt.
No matter what the temperature salt will melt the ice.
This is not true! In the concentrations we use on our roads salt does not melt ice below minus eight degrees centigrade and is less effective at temperatures below minus five degrees centigrade.