The woman was not injured but a bullet hit the back of her car, the Times of Northwest Indiana in Munster reported Monday.
The 33-year-old woman from Lansing, Ill., told officers she was driving slowly on a street in Gary Sunday because of potholes when a car began following her closely.
When she braked to get the driver to back off, he got in front of her as both vehicles entered Interstate 80/94. The driver of the other car pulled up beside her, pointed a gun at her and shot four or five times before pulling away, police said in a statement.
The incident was the second in a week on Interstate 80/94 believed to involve road rage. A man driving home from work was shot and injured Wednesday in Lake Station.