A study is aimed at development and research of mathematical models and algorithms for traffic flows control in urban road networks. An optimal control problem statement for traffic flows in urban networks is given. A feature of the problem is that the model of control object is presented in finite-difference equations. A control is constrained by the durations of active phases of traffic lights at intersections. The solution is a control program that determines the moments for phase switching. A variational genetic algorithm is used to solve the problem. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the 13th International Symposium “Intelligent Systems” (INTELS'18).