The folks in Alberta know better than to buy a Dodge.

Seriously, conditions in the prairie provinces are much different than the rust belt of the states. Less rainfall, lower humidity, salt would be less effective with the colder winter temperatures and lower population densities, so fewer vehicles.
1) The "grain of salt" comment, pun intended? I have to admit that I usually am pretty much in agreement with what DP says, except that some of our tastes differ. With you two going at each other all the time, I have to think you're brothers or at least cousins.
2) I kind of doubt that. Indiana has far more people and roads than New Hampshire. And with their warmer temperatures, the salt is more corrosive. Let's not forget that Indiana also has higher summer humidity.