Transportation demand management has been implemented in Seoul to realize the transit-oriented development for its evolution into an eco-friendly city. The policies include reorganizing road space, restricting the operation of fifth-grade vehicles, increasing parking fees, and expanding shared bicycles. The Seoul Metropolitan Government monitors traffic changes by installing cameras at the point of entry into the city center for policy assessment. Furthermore, it acquires data about the number of public parking lots and shared bicycles. In this study, a quantitative evaluation of green traffic promotion area designation and implementation policies is conducted using various data. The analysis is conducted by classifying the effects of increasing and reducing eco-friendly transportation, and the benefits of reducing public bicycle use, air pollution, and parking costs are considered. The benefits of reducing air pollution by reducing traffic volume and the benefits of reducing parking costs by decreasing the number of parking units are calculated and estimated. The analysis shows that the cost-benefit of reducing air pollution by reducing traffic volume is approximately 42.5 B KRW/y. This qualitatively translates to approximately 1.3 M trees. The cost benefit of reducing the number of parked cars is estimated to be 18.2 B KRW. In addition, the average daily use of public bicycles, an eco-friendly mode of transportation, increases by approximately 390 units, as proven statistically. The results of this study confirm that transportation demand management enables eco-friendly goals to be achieved. Finally, It is expected to be used as an indicator for the Seoul Metropolitan Government's public transportation-oriented development policy.