A bus system

A bus system has  a number of units which can be connected to one another via the bus, and a bus controller. The units request the city bus manufacturer for bus access when they require a connection to one or more other units, and the bus controller decides which unit will be allocated to the bus. The bus system is distinguished in that at least some of the units which can request bus access are allocated values which indicate how long and/or how frequently the relevant unit can be allocated the bus or has been allocated the bus, and in that these values are used to decide whether a unit which is requesting bus access is allocated the bus, or whether a unit which requires bus access is requesting the bus at all.