Essentially, the Automatic Trails are racing tracks that vary, based on the course's environment. They include a metal pole running along a digital cable, a millipede or even a river stream.
The Automatic Trails are sections of the various race courses in Sonic Riders. While on Automatic Trails, the playable character is automatically controlled and requires no input from the player. In most cases though, the player can move faster down the Automatic Trails and gain Air at the same time by quickly rotating the Control Stick in a clockwise direction (or alternately press the left and right arrow keys in the PC version).