International Journal of Mathematical Research 2311-7427 2306-2223 International Journal of Mathematical Research The Method of Determining the Function of Traffic Costs for the Node with Unregulated Flows of Requests International Journal of Mathematical Research International Journal of Mathematical Research 12-2013 2013 12-2013 12-2013 2 6 45 57 30 Nov 30 Nov Modeling of transportation networks with the purpose of optimization is a vital problem. The difficulties of numerical solution of optimization problems for networks mainly depend on the analytical definition of the function of traffic costs. We provide a developed mathematical model of transportation network based on the generalized Erlang time distribution. We also propose a classification of nodes. For the case of the node with unregulated intersection of multichannel lines as a system of mass service, we obtain an analytical realization of the function of traffic costs. We describe a method of determining the parameters of the generalized Erlang law from experimental data.