A system for automatic unloading of parcels from a container or trailer includes a base belt (310), a plurality of inserts (320, 322, 420, 422, 520, 522) and an automated unloading apparatus (200) with a ramp (230) and a conveyor (226). The ramp (230) is configured to pass under the base belt (310) and the conveyor (226) is configured to remove a plurality of items (370) when the automated unloading apparatus (200) moves into an interior of the container or trailer (350), and the base belt (310) is configured to be installed in a first section (360) of a floor (356) of the container or trailer (350), and the plurality of inserts (320, 322, 420, 422, 520, 522) is configured to be installed in a second section (362, 364) of the floor (356) of the container or trailer (350), such that the plurality of items (370) is either located on the base belt (310) or on the plurality of inserts (320, 322, 420, 422, 520, 522).