According to police reporter Joseph P Barrett, the term Black Friday emerged from the Philadelphia Police Department's traffic team.
"The cops used it to describe the worst traffic jams which annually occurred in Center City on the Friday after Thanksgiving," he explained in an article on Philly.com. "It was the day that Santa Claus took his chair in the department stores and every kid in the city wanted to see him. It was the first day of the Christmas shopping season."
In an article he wrote in 1960, Barrett claims he appropriated the term for a front page story for the Evening Bulletin, to describe the awful traffic conditions. Repeated use by local media saw the term gain a new tradition.
"Today the term seems lost in antiquity, but it was a traffic cop who started it, the guy who directed traffic with a semaphore while standing on a small wooden platform, in the days before traffic lights. But that was a long time ago."