MADISON, Wis. — A delivery truck ran over a cyclist's head, leaving him only with a concussion and a mangled helmet. Ryan Lipscomb, 26, was shaken up, especially after he saw the condition of his helmet. "I didn't see it coming, but I sure felt it roll over my head," he said. "It feels really strange to have a truck run over your head." Lipscomb, a graduate student in medical physics at the University of Wisconsin-Madison, was riding swiftly down a bike path in Madison Friday afternoon. As he approached an intersection where he said he had a green light,...