In and around town, they use salt.
When everyone used studded tires, salt wasn't required - the studs roughed up the ice.
We're over 50% on unstudded tires now and that results in polished snow/ice. = salt.
There has always been a few guys riding all year, mostly dirt bikes, on studded tires.
Probably not the safest thing, but with a huge fun factor.
I have a cousin who rides all winter. He says that as long as the streets are plowed, he rides to work. I don't know what happens if there is a major snowfall while he is at work.
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By contrast, someone posted on another forum that he stores his bike during the winter, and he lives in California, and says the temperature rarely drops below 55 Fahrenheit.