By Lilly Chapa
More than 20 million metric tons of road salt is spread on U.S. roads each winter to prevent hazardous driving conditions during icy weather. In the car wash industry, that means lots of reasons to wash, and lots of revenue opportunity.
BACKGROUND
Road salt is a tried-and-true method to treat slippery roads that has been used since the 1930s, with an average 5,000 metric tons spread each year. The dramatic rise in popularity – and sheer amount – of salt to treat roads is due in large part to how effective it is: the American Highway Users Alliance found that road salt reduces collisions by up to 85%.
THE SCIENCE
The material used on icy roads comes in the form of large crystal rock salt, which is typically either sodium chloride-based – like table salt – or calcium chloride-based, a cheaper option. These chemicals react with water to lower its freezing point, slowing the formation of ice on roads and allowing car tires to gain traction on the pavement.
Water is required to activate the reaction, so some road crews will pretreat roads with a brine, or mixture of water and salt, to keep ice from forming. If snow or ice is already on the ground, salt is spread to break the bond of the ice on the road, resulting in a slush that is much easier and safer to navigate.
However, if the road temperature falls below 15 degrees Fahrenheit, the salt can’t penetrate the ice effectively, and road crews will switch to sand to provide more traction.
“ When steel—an alloy of iron—meets water and oxygen, a chemical reaction creates iron oxide, more commonly known as rust. This process is accelerated by salt.”
Which States Use the Most Salt Per Mile of Road?
ADVERSE EFFECTS
Road salt not only reacts with ice on the ground but with the metal on vehicles. When steel – an alloy of iron – meets water and oxygen, a chemical reaction creates iron oxide, more commonly known as rust. This process is accelerated by salt, often along the bare steel components underneath the vehicle. The brake and fuel lines are especially susceptible to damage caused by road salt. Drivers pay about $3 billion each year to repair damage caused by de-icing methods, according to AAA.
A driver may navigate their vehicle through salt-treated roads and feel confident parking it in a dry garage and giving it a quick wipedown, but any residual salt – often hiding out of sight along the undercarriage or in small scrapes – can eat away at the steel or brake lines without being detected.
