The Zheleznitsa tunnel, part of the Struma Motorway, is about 2 km long, with two separate pipes for each direction, and is the longest road tunnel in Bulgaria. It was built according to the New Austrian Tunneling Method. It includes two service roads on both sides of the facility. It is equipped with all safety systems, energy efficient lighting, ventilation, video surveillance, fire alarm, intelligent traffic management system, emergency SOS booths, electronic access control system. The project also includes the implementation of several unique sites, including a medical helicopter landing pad immediately after the tunnel, traveling in the direction to Kulata.