First the good about salt brine. The Michigan Department of Transportation found that 40 percent of rock salt spread on roads ends up on the shoulder. While salt brine, a mixture of 23% salt and 77% water, is applied wet and remains on the roadways. The efficiency of salt brine not only helps to keep the roads effectively more ice free, it also adds a cost savings with less salt used and more of it staying on the roads. Now the down side, the corrosion and rust we all loathe to see on our vehicles is caused by acid created when salt reacts with moisture in the air. Rock salt will remain in crystalline form until humidity reaches 70%, but salt brine already has the ability to corrode your vehicle, being already in solution. In addition, salt brine more easily reaches all the nooks and crannies in your vehicle’s under carriage because of its liquid form. Whether your local road works uses brine or rock, one way to help protect your car is to wash it regularly and especially after a storm, when road crews are employing deicing measures.