Our team is heavily involved in the Tunnel Golubinja project, contributing to the infrastructure development of the Zenica–Žepče section of the Pan-European Corridor Vc in Bosnia and Herzegovina. The project involves the construction of a 3,659-meter-long twin-tube highway tunnel designed for vehicular speeds of up to 100 km/h, improving transportation efficiency on this vital route. We have developed two design options for the tunnel's ventilation system: one with fans installed at the portals and another with jet fans distributed along the tunnel length. The ventilation systems are designed to manage airflow, ensure air quality, and provide smoke extraction capabilities in case of fire. The tunnel construction follows the principles of the New Austrian Tunneling Method (NATM), which is suitable for the complex geological conditions in the area, allowing for continuous monitoring and adaptive support measures during excavation. The twin tubes are connected by 15 cross passages, including three vehicular cross passages for emergencies or maintenance and twelve pedestrian cross passages for safe evacuation routes. The European Bank funds the project for Reconstruction and Development (EBRD). It adheres to FIDIC Yellow Book guidelines, ensuring compliance with international construction and project management standards. Our team plays a pivotal role in the Tunnel Golubinja project. We were responsible for the preliminary design, geotechnical assessments, structural analysis, and development of design specifications. We also provide crucial technical assistance for the Employer during the construction phase and ensure strict compliance monitoring with the Contract.