In a transmission controller for the open-loop and/or closed-loop control of the operation of an automatic or automated manual transmission of a motor vehicle, a shifting strategy of the transmission control unit controls the operation of the transmission in an open-loop and/or closed-loop manner based on driving status data and/or driver intention data. The shifting strategy of the transmission control unit influences a gear change from a current actual gear into a target gear based on available environmental data. In the event of a required down-shift from a current actual gear into a lower target gear, the transmission control unit is configured to take into account available information relating to a traffic light status, in particular relating to a change of a traffic light status of a relevant traffic light.