 This was helped by Bigfoot not racing for points in the 1989 championship, leaving Grave Digger as the most popular truck on the tour.When TNT became a part of the United States Hot Rod Association in 1991, Anderson began running on the USHRA tour and debuted his first four-link truck, Grave Digger 3.Throughout the 1990s, the popularity of the truck grew and forced Anderson to hire other drivers to run other Grave Digger trucks.