A method of, and a toll-collecting system (SYS) for, determining whether at least one toll road section is being used by a vehicle (FAR), wherein the position of the vehicle (FAR) is determined by means of at least one position calculating system (POS) and the determined position is implemented to ascertain whether the road section being used is a toll road section, and wherein the vehicle (FAR) has, in addition to said position calculating system, a transmitter/receiver unit (SEE) that is adapted to exchange data (DAT) with a cellular radio network (FUN), and that to each cell (ZEL) of the radio network (FUN) at least one cell identifier (ZID) is assigned, and when there is at least partial failure of the position calculating system (POS) the at least one cell ID (ZID) is implemented to ascertain whether the road section being used by said vehicle (FAR) is a toll road section.