Abstract
It should be very valuable to be able to make a reliable estimation of the unknown cells of an origin- destination matrix (partial matrix). In estimating these cells it is desirable to use as much relevant information as possible. This information may consist of traffic counts, survey data, socio-economic data, etc. Some examples of the fast calibration program FASCAL show, how the unknown cells of a partial matrix can be estimated. It is concluded that the determining factor for the accuracy is the a priori knowledge of the unknown parameters of the model.