The total demand scale: A new measure of quality for static and dynamic origin–destination trip tables

We propose a measure of quality for origin–destination (OD) trip tables estimated from link counts. This measure, called the total demand scale, is based only on the estimated OD trip table and on the assignment matrix used to estimate it. It is independent of the OD estimation method and of the technique used to overcome the underdetermination of the OD estimation problem. The total demand scale measures the intrinsic under-determination related to the OD estimation problem, considering only the network topology and the underlying route choice model. Because it identifies the level of arbitrariness introduced by the a priori matrix in the estimation process, our approach helps to evaluate if an important amount of resources must be invested for the a priori matrix, or if the available link counts contain sufficient information. The computation of the total demand scale enables to identify at zero additional cost those OD pairs such that no measurement is available on any path linking them. A MATLAB code for the computation of the total demand scale is also provided.