Today, sustainability has entered our entire sphere of life. The increase in the world population has further increased the importance of this concept. Transportation, which is one of the indispensable elements of human life, must also be carried out in a sustainable manner. For this purpose, countries hold various meetings under the umbrella of the United Nations at certain periods. As a result of these meetings, countries make commitments to reduce greenhouse gas production in the future. The share of energy in greenhouse gas production is around 72%, and transportation contributes 15% to energy-related greenhouse gas production. In order to further reduce the share of transportation, transportation vehicles can be transformed into vehicles powered by electricity instead of fossil fuels. With the development of technology in transportation routes, the construction of longer bridges and tunnels shortens the distances and thus ensures less carbon emissions into the air. In this study, the transportation sustainability of the New Zigana Tunnel, Türkiye's longest highway tunnel, was examined. The New Zigana Tunnel passing through Zigana Mountain contributes to sustainable transportation. Because the newly built tunnel passes 600-700 meters lower than the old one. Thus, it not only shortens the distance economically but also reduces carbon emissions from vehicles by 15% without going up to an altitude of 1800 meters. It is thought that the New Zigana Tunnel will reduce the impact of the severe climatic conditions brought about by the winter season on the highway passing at high altitude, and will also reduce the number of accidents caused by snow and icing in transportation vehicles. At the same time, it will undoubtedly minimize transportation disruptions caused by accidents. The tunnel has reduced the effects of landslides in seasons with high rainfall and has become an alternative route against road closures caused by stone falls caused by physical dissolution. With the decrease in means of transportation passing through Zigana Mountain, the tunnel, which minimizes the risk of accidents for wild and abandoned/unabandoned pets, will prevent material and moral accidents from occurring.