An automated storage and retrieval system includes a grid-based rail structure and a plurality of remotely operated vehicles arranged to operate on the grid-based rail structure. The automated storage and retrieval system includes a locking device arranged in a zone of the grid-based rail structure where a human and/or a robotic operator is permitted to interact with the remotely operated vehicle or contents of a storage container that the remotely operated vehicle is carrying. The locking device is arranged to lock the remotely operated vehicle against accidental displacement prior to interaction with the human and/or robotic operator, and wherein the locking device being arranged to unlock the remotely operated vehicle once interaction with the human and/or robotic operator is no longer required.