Samenvatting
A method, based on collection of data in the train, which can be used to determine the extent of the kilometers travelled by the passengers, is discussed. A characteristic of the data acquisition method is that only the different kinds of tickets should be counted. In order to estimate the extent of the passenger kilometers, it is not necessary to use the length of the perceived journeys. However, in order to estimate the extent of the journeys the length of the perceived journeys should be used. The method is shown in a mathematical model.