The amount of salt many places in the Northeast US use is unreal. It's at least partially part of a cycle of dysfunctional political incentives, wherein many of the states that dump millions of tons of salt on the roads should have requirements that vehicles be equipped with winter tires, but adding additional costs and barriers to driving is considered unfair because we've designed so much of our built environment to simply require a car to go anywhere.

So, we have people out there driving around year round on bald summer tires, and to make sure they don't kill themselves or cause major issues, turning the roads "black and wet" with loads of salt becomes the solution.

It's totally unsurprising that the salt is harmful to the environment. I imagine that saving people the expense of winter tires in this way may actually be a false economy, given that the salt rapidly accelerates the destruction of cars themselves and the concrete infrastructure it's applied to.

Politicians largely don't want to touch this issue, I think, because they're often the target of blame when the roads are insufficiently cleared and people have trouble getting around.

As an example: several years ago in NYC, a sudden snowstorm caused devastating gridlock around the city and the mayor was dragged over the coals. In response, for the rest of that winter, whenever there was even a hint of a chance of snow, the city would preemptively put down an extraordinary amount of salt. At one point that winter, I stepped out of my office and the street was completely covered thick layer of salt, which was being pulverized by traffic into a dense cloud that looked like heavy fog. Just walking around the air tasted strongly salty. It never snowed, or even rained, so all of that salt just sat there for days.