But what’s up with those trucks? They’re working to protect drivers from slippery conditions by spraying rock salt or a solution of salt water to prevent ice formation. … So if there’s snow, sleet or freezing rain and the ground is 32 F or colder, solid ice will form on streets and sidewalks.

How does salt work on icy roads?

Why does salt melt ice and snow? Salt causes a phenomenon called freezing point depression, which means it lowers the freezing point of water. Water normally freezes at 32 degrees Fahrenheit, but when you add salt, that threshold can drop as low as 20 degrees Fahrenheit.

How does salting the roads work?

Road salt works by lowering the freezing point of water via a process called freezing point depression. The freezing point of the water is lowered once the salt is added, so it the salt makes it more difficult for water to freeze.