9 In the colder parts of the world (such as northern Europe and North America) where winter snow and ice can cause huge disruption to everyday life, local governments ‘grit’ the roads (actually rock salt, a mixture of salt and grit) when they believe weather conditions warrant it. If you were in charge of this operation, what would be the main decisions that you would need to take, and what factors would you take into account in order to make these decisions?