Conveyance system and conveyance control method

This invention describes a system for vehicles that can drive themselves. It combines two ways of driving: one where the vehicle follows a marked line on the ground, and another where it drives autonomously without a line. The system uses the vehicle's position or how far it has traveled to decide when to switch from autonomous driving to looking for and following the marked line. When it's time to switch, the vehicle will drive in a specific direction until it finds the line.