A methodology for locating link count sensors taking into account the reliability of prior o-d matrix estimates

The paper proposes an innovative methodology for addressing the issue of the optimal link count sections location, based on the proposition of a reliability measure in which the prior accuracy of the o-d matrix estimate, that is its statistical distribution rather its prior punctual estimate, is explicitly considered, together with its posterior distribution conditioned on a given subset of link count locations. Notably, the proposed measure, under the mild assumptions of prior normal distribution and through appropriate algebraic rotations of the reference system, is proved not to depend on the unknown values of the counted flows, and this is actually the key point allowing for effective implementation of a fast and operational procedure based on this mathematical framework, in the sense stated in the introduction. By way of an example, toy network and real network applications are presented, in order to show how a heterogeneous level of knowledge across o-d pairs may lead to the choice of counting sections different from those resulting from the commonly adopted procedures. The proposed methodology allows for a more effective theoretical interpretation of the phenomenon and leads to a very efficient computational procedure, suitable also in real size networks, whose results outperform those obtained with the methods to date available in the literature.