The paper is dedicated to the problem of OD-matrix estimation and reconstruction. The authors carried out a review of the literature of foreign and Russian authors on the subject of the estimation and reconstruction of a trip matrix. The most effective method of optimal plate scanning sensors location on the road network is noted. To improve this method, the new optimizational model is developed for the road network of general topology. The developed model allows to maximize the probability of fixation of the most significant traffic flows throughout the whole route. Simulation with experimental data is carried out on the transportation network of St. Petersburg.