Transport vehicle system

A transport vehicle system comprising:

• a transport vehicle including two transport-vehicle-side supports disposed to be spaced in a traveling direction such that, for a roll material including a product wound around a core, extending directions of the core are parallel to one another;
• a buffer into which the roll material is temporarily carried from the transport vehicle before being transported from a first process to a second process that is a process following the first process;
• and
• a controller configured to control the transport vehicle, wherein
• the buffer includes two buffer-side supports disposed to be spaced in the traveling direction of the transport vehicle such that the extending directions of the core are parallel to one another, and
• the controller includes:
• a determination unit configured to, based on the winding direction of the roll material before being carried into the buffer and the winding direction of the roll material required in the second process, determine whether the winding direction needs to be changed;
• and
• an instruction unit configured to, where the determination unit has determined that the winding direction needs to be changed, cause the transport vehicle to perform a winding-direction-changing operation including an operation of reversing the traveling direction of the transport vehicle and an operation of changing placement of the roll material between the two buffer-side supports.