why does a car rust out quickly in places where salt is placed on roadside to melt ice?

Answer 1

The salt melts the ice. The car goes over the water, gets splashed. Salty water wets the car. Water evaporates leaving the salt on the car. Everytime there is some moisture on the air, salt re-dissolves and attacks the metal. This will continue until you wash your car.

Conclusion. If you leave in snow country where salt si spread wash your car during the winter frequently.

Answer 2

For rust to occur you need an anode, a cathode, a conductive path and an electrically conductive solution. The car body can quite easily make the anode, cathode and conductive path. Water alone does not conduct electricity but salt solutions do, so if you have salt on your vehicle any moisture on the vehicle will create a conductive path and allow rusting to occur.

Answer 3

Salt and chemicals used on the road can eat through the paint. You should always wash your car after you've driven on a salted road.