For those of you who think salt doesn't work below 15 degrees you're crazy. Take a heavy salt water solution put a piece of iron/steel in it and put it in your freezer. Look at it in a few hours and report back. Sodium chloride is a fairly strong oxidizer and will oxidize uncoated ferrous metals rapidly. If you were able to do a comparison based only air exposure and exposure to salt and air you would likely find that the direct salt contact will oxidize ferrous metal thousands of times faster than air. If it's wet and salty it will be thousands of times faster than salt and air. Therefore every second salt of anti icing compounds are on your cars uncoated metal surfaces you can be sure it's oxidizing those surfaces rapidly. People are driving their cars way longer than years past and the cars drivetrains are lasting much longer than years past. I've replaced numerous oxidized brake components in the last 10 years on many different cars. You can tell where the cars came from and if the owner washed the undercarriage. The best car wash you will get is the one you do yourself with a high pressure spray..