Total length of the tunnel and pertaining north and south connection roads is 9,2 km. As part of Zagvozd – Baška Voda connection road the following will be constructed: St. Ilija tunnel with total length of 4.250m, more than 4 kilometers of access roads, overpass St. Križ and two underpasses of the alignment and a grade-separated intersection on the Adriatic tourist road.
St. Ilija tunnel is a main object with total length of 4.250 m. St. Ilija tunnel has biggest limestone overburden in Europe, and its height exceeds 1.300 m. The tunnel will have two separated tunnel pipes primary and secondary. The primary pipe will be used for regular traffic with two traffic lanes. The secondary pipe will be used for rescue and evacuation needs. Tunnel will be constructed with constant three percent slope decrease from north to south. Due to the overburden height of over 1.300 m, the tunnel represented a special challenge for all who worked on its breakthrough.
Construction of Zagvozd – Baška Voda connection road and St. Ilija tunnel will provide a high quality road connection between Zagreb-Dubrovnik motorway and part of the adriatic coast so called „Makarska riviera“.