Metropolitan areas encounter serious problems in the field of transportation, including increasing travel time, congestion in some urban areas, especially the city's central boundaries and air pollution. Transportation planning is one of the approaches that has come to the aid of city officials during these years and has reduced transportation problems in cities by designing and implementing transportation projects. Since the implementation of transportation projects in cities is generally costly, it is necessary to reduce the negative economic, social and environmental impacts through other approaches, including appropriate planning in the distribution and placement of users.. . In order to assess the effects of this planning, a model should be available that simultaneously addresses the effects of changing transport and land use systems.
The purpose of this study is to propose an innovative methodology that provides population and employment placement during the process of transportation network design, which will results in improvement of sustainable transportation in major urban areas. In this model, the amount of population allocation or additional employment for each area is calculated from the social cost of addition of a person to the population or employment of the under study on yearly basis. Also, in this model, the selection of transportation projects is carried out according to budget constraints, and the indicators of sustainable development are calculated for each transport scenario. The scenario that has the least destructive effects on the transport action of the city will be chosen as the preferred scenario. The proposed method was implemented on the Sioux Falls network, for which the population and employment placement caused improvements in indicators such as air pollution, traffic congestion and transportation costs. The results have shown the effectiveness of the proposed method.