There is next to no salt being used in AB. Here the substance of choice is sand and gravel, with some ice melting pellets (not salt, doesn't seem to rust cars) used in extreme cases. Same in Sask. as far as I know. Cars don't rust out here nearly as bad as the cars in places like Montreal (where I grew up). The amount of salt used in that town is insane. The salt not only eats the cars away, it damages concrete and asphalt, too.
The really bad cars in terms of rust were the early 1980s Fiats (124,128, and Mirafioris), Alfa Romeos (pretty much all, but they weren't driven in the snow as much). You could literally see the salt eating away the Fiat bodies in real time.
Montreal actually picks up the snow. The use giant snow blowers and load the snow (with salt) onto dump trucks and haul it away. They used to dump it into the St. Lawrence river, until the Quebec Environmental Dept. made them stop as it was raising the salinity level in the St. Lawrence river. Now they just dump it into open fields. They end up making huge snow hills. Most years, it can take until the middle of June until the snow hills melt entirely (melting process slows down as the hill melts, as the accumulated mud that is left behind slows the heating from the sun).
Kostas