Why do trucks spray liquid onto the street before a storm arrives?
It may seem dangerous to add a liquid to a street that might freeze, but the liquid is a chemical that actually inhibits ice from forming and inhibits any snow or ice that does form from sticking to the pavement. The liquid chemical called calcium magnesium acetate is a form of salt, and it helps prevent frost or black ice. When there is a forecast of roadway frost or freezing temperatures that may cause road icing problems, crews may perform anti-icing on selected elevated structures like bridges and overpasses and known hazard areas in the hills and on critical locations like Marine Drive. A pre-storm treatment can be made as long as the storm doesn’t start out with above freezing temperatures and rain, washing the chemical away.
