This paper presents a deterministic solution methodology for Transit route Network Design Problem (TrNDP). The main objective is to design a set of bus routes minimizing both users and operator costs while satisfying some constraints; such as minimum demand trips coverage, maximum bus route length and route directness. The proposed methodology provides an efficient set of circular closed bus routes. The formulation of the methodology consists of three parts; 1- representation of transit route network and input data, 2- representation of transit route network objectives and constraints as mathematical programming, 3- the structure of the solution methodology for bus route design. The methodology structure has been tested through Mandl’s benchmark network problem. The test results showed that the methodology developed in this study is able to improve a given network solution in terms of number of constructed routes, transit service coverage, transfer directness, and solution reliability. Based on the presented methodology, a more robust network optimization tool would be produced for public transportation planning purposes.