Problems of optimization in natural science, technology, economics, and management are of great interest. Students also usually find them intriguing. However, the selection of such problems in introductory undegraduate physics textbooks is very limited and should be broadened. To that end, a model of traffic flow optimization, simple enough for undegraduate students to analyze, is presented. Calculations of the main optimal parameters of cars' flow on a one-lane freeway, based on this model, are compared with experimental data.