It snowed, so the city of Park Ridge went and plowed the streets. In at least one spot, it plowed the snow out of the street and onto the sidewalk. Some time later, a woman named Lorraine walking on the sidewalk encountered the snow pile. She couldn’t get around it, so she tried to cross the street right there, even though there was no crosswalk. While doing that, she was hit by a car. Lorraine sued Park Ridge. The city, she argued, had a duty to maintain its sidewalk in good condition. Leaving a pile of snow …