Method for operating, in particular for controlling, a system, wherein the system comprises vehicles (2, 3, 4), a central control unit and at least one transceiver module, which is connected to the central control unit by means of a bidirectional communication channel, arranged in a stationary manner and comprises a transmission spatial range, in particular a transmission cone, wherein each vehicle (2, 3, 4) comprises a respective transceiver module, each of which in particular comprises a respective transmission spatial range for bidirectional communication with the stationarily arranged transceiver module and/or with a vehicle, wherein each transceiver module comprises at least one controllable light source (1, 5, 6, 7, 8, 9, 10, 11, 12, 13) and a light sensor, in particular a light source (1, 5, 6, 7, 8, 9, 10, 11, 12, 13) of visible light and a light sensor for visible light, wherein the central control unit transmits travel instructions to the vehicles (2, 3, 4) by means of the stationarily arranged transceiver module, wherein a first vehicle located in the transmission spatial range of the stationarily arranged transceiver module relays a travel instruction to a second vehicle (2, 4) located beyond the transmission spatial range of the stationarily arranged transceiver module, wherein the second vehicle (2, 4) transmits data, in particular status information, to the central control unit by means of the first vehicle and the stationarily arranged transceiver module, wherein each vehicle (2, 3, 4) comprises a position determination means, in particular comprising an odometric sensor and/or a GPS sensor, and transmits its positional data, determined by the position determination means, to the central control unit by means of the stationarily arranged transceiver module and/or of the first vehicle, wherein each vehicle (2, 3, 4) determines the positional data of vehicles located in its spatial transmission range, in each case relative to itself, and transmits these determined relative positional data to the central control unit by means of the stationarily arranged transceiver module, wherein the central control unit determines position corrections from the positional data of each vehicle (2, 3, 4), the relative positional data of the vehicles (2, 3, 4) and the position of the stationarily arranged transceiver module, and transmits said corrections to the vehicles (2, 3, 4), characterised in that the travel instruction for each vehicle (2, 3, 4) comprises - a travel destination and - a starting point and - a travel route and - a speed and - a release for a track portion of the travel route and a maximum travel time, wherein a first vehicle which, when at the travel destination of its travel instruction, is located beyond the transmission spatial ranges of all the other vehicles (2, 3, 4) and of the stationarily arranged transceiver module, automatically returns to the starting point of its travel instruction, wherein the current actual position of the first vehicle, as determined by means of the position determination means, is controlled towards a current target position in accordance with the travel route, wherein, as soon as a first vehicle stays beyond the transmission spatial ranges of all the other vehicles and of the stationarily arranged transceiver module for a period of time that is longer than the specified maximum travel time in its travel instruction, the central control unit transmits to a second vehicle a travel instruction comprising a travel route that is identical to the travel instruction of the first vehicle, wherein, once it has established a communications link with the first vehicle, the second vehicle receives the status information of the first vehicle, stores it, travels back to the starting point of the travel instruction of the second vehicle and transmits the status information of the first vehicle to the central control unit, wherein the second vehicle (2, 4) receives a first and a second travel instruction, wherein the second vehicle (2, 4) executes the first travel instruction and stores the second travel instruction, wherein, once it has established a communications link is established with a further vehicle, the second vehicle (2, 4) transmits the second travel instruction to the further vehicle. - a travel destination and - a starting point and - a travel route and - a speed and - a release for a track portion of the travel route and a maximum travel time,