In many places of the globe, the first thing that will be placed on the road upon the appearance of ice is salt. Additionally, you can see individuals sprinkling salt on the sidewalks and stairs.
Why do people salt the roads in winter? This helps minimize the accumulation of ice on the road, which enhances driving safety greatly during the winter months. The salt used on roads and sidewalks is substantially identical to the table salt used in cooking. It is not, however, refined like table salt. This is why it is often gray or brown.
Wondering exactly how salt makes the roads safer? You may have heard people say that salt melts ice. However, this process is a little more complicated. This is related to a concept called freezing point depression.
At 0 ° C, liquid water condenses into ice. This is the moment at which it becomes immobile. When salt is added to water, the water molecules find it more difficult to form ice crystals. This results in a decrease in the freezing point of water to around -9.4 ° C. Even salty roads might get coated with ice below this temperature.
The process works best when the salt is already mixed with water when it hits the road. This is why brine is used instead of rock salt in many cities. At very low temperatures, and can be seen on icy roads. Sand does not melt ice but provides a less smooth riding surface.
Salt is an inexpensive and efficient technique to make winter roads safer. Recent research, however, has shown that this practice is detrimental to the ecosystem. The rock salt used to treat roads winds up in local bodies of water and even in groundwater. When used in high amounts, it may deplete the area’s freshwater supply and negatively affect plants and animals that rely heavily on water.
Salty roads can also cause elevated chloride levels in lakes and rivers. This chemical can be hazardous to plants and animals. In addition, salt is corrosive and can damage roads, bridges, and vehicles. These impacts have prompted some groups to advocate for other solutions for icy roads, such as sand.
However, driving in colder months can be dangerous with or without salt on the roads.