Not too much. The do sand them, but all salt tends to do is make a layer of water on the existing ice. They concentrate their efforts on scraping all ice off the main roads and putting lots of sand down, plus doing a rough plow on the side roads with a little sand. The result is, the main roads and highways are actually excellent and keep rolling all winter but the side roads can become almost impossible to even walk across. Every winter people scream at the Muni government about it, and every winter the muni ignores them

That's not to say the city does nothing. But its efforts tend to be strange and perverse. My favorite is when the parks workers come out with their expensive mini-snow plows and clear off every spec of new snow from the solid two inches of ice on the bike trails! Yeah, we wouldn't want that snow giving anyone any traction or anything. But this year I'm going to ride on all of it like a leaf on the wind. A huge, lumbering leaf.