This study aims to propose and investigate a theoretical maximum traffic flow method. Furthermore, we propose a merging timing control based on the results obtained from this method, which are verified using actual automated guided vehicles. The results (micro-level optimization) enable automated guided vehicles to achieve a fabrication level optimization (macro-level optimization). Engineers working in the field of automated guided vehicles have found that there is an optimal headway distance that achieves a maximum traffic throughput when automated guided vehicles operate with merging points. ''Zipper merging'' is known to be a suitable merging method resulting from ''Jamology.'' In this study, first, we will verify the results using the ''Zipper merging'' simulation model. Second, we develop a mathematical model and verify its simulations and experiments using actual automated guided vehicles. Finally, we develop a merging timing control to augment transfer flow and verify the effects using a small full fabrication simulation. We predict that this control will improve factory model throughput when used in practical applications.