The chunks of snow and ice can come from overpasses and bridges, but it's mainly sliding off cars that people don't clear off.

Illinois law does not specifically state drivers must scrape snow and ice off their vehicles prior to driving, Master Sergeant Calvin Dye Jr. wrote in a Dec. 9 email to the News-Democrat. However, there is a state statute that says “ windshields must be unobstructed and equipped with wipers.”