The term 'Freeway Problem' refers to a traffic issue caused by congestion on highways. It is characterized by a 'SNARL' of vehicles, a 'LINEUP' of cars, and a 'pileup' of vehicles. A SNARL is a tangled mess of vehicles, while a LINEUP is a long row of cars waiting to move forward. A pileup is a large number of vehicles that have crashed into each other due to the congestion. All of these issues can lead to traffic delays and accidents.