Salts That Melt Ice: The Science of Winter Roads

Road salt works by lowering the freezing point of water, a process called freezing point depression.
Sodium chloride is the most common de-icing salt, but it’s less effective in extreme cold.
Calcium chloride works at lower temperatures, releasing heat as it dissolves.
Magnesium chloride is another option, often used in areas with very cold winters.
Potassium acetate is an eco-friendlier alternative, commonly used near airports.
Salt brine solutions are sprayed before storms to prevent ice from bonding to roads.
Salts don’t instantly melt ice—they speed up melting by disrupting water’s crystal structure.
Excess road salt can damage cars, concrete, and nearby vegetation.
Engineers balance safety with environmental impact by mixing or limiting salt use.
Without road salts, winter travel would be far more dangerous and less reliable.