Abstract: Methods and apparatus for selecting and combining items in an outbound container through the use of autonomous vehicles, each of which includes means for automatically loading and unloading a payload, to perform both transfer and transport functions in moving containers of items within a workspace via a network of roadways. Under computer control, said autonomous vehicles transfer and transport case containers of item units between incoming receiving stations, intermediate storage locations, and outgoing order-assembly stations where entire containers or individual item units are combined in the outbound container.