The use of automated guided vehicles (AGVs) as transporters and mobile workstations in automated assembly lines is on the increase. This is due in part to the flexibility AGVs introduce in the design of production lines. In this paper, models for the management and control of material flow through AGV based production lines are developed. The use of the models permits the line designer to optimally determine the launch times of successive unit loads of parts into the line to minimize production makespan while balancing between line idleness and the idleness of vehicles employed on the line. The use of the models for AGV based production line design purposes is demonstrated through example problems.