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The Sveti Rok Tunnel is a highway tunnel in Lika, Croatia. It is 5,679 m (6,211 yd) long and it passes through the Velebit mountains. Sveti Rok Tunnel is located on a part of the between highway exits Sveti Rok and Maslenica on the A1 highway (Zagreb - Dubrovnik). The village Sveti Rok and village Maslenica are located near the tunnels respective northbound and southbound entrances, but they are accessible only by highway exits. The western shaft of the tunnel was opened in on 30 June 2003, and the eastern shaft was opened on 30 May 2009.
Contents
Map of Tunel Sveti Rok, Croatia
Description
The northern portal of the tunnel is located at 561 m.a.s.l., while the southern portal is located at 510 m.a.s.l.. The east tunnel tube is slightly longer than the west one as they are 5,679 metres (18,632 ft) and 5,670 metres (18,600 ft) long respectively. The tunnel tubes are 25 metres (82 ft) apart, and are connected by 4 passages for vehicles and 15 other passages, accessible on foot.
Since the Sveti Rok Tunnel and the Mala Kapela Tunnel are of similar lengths, and their construction has been carried out concurrently, their appearance and properties are very similar. Therefore the tunnel also comprises 7.7 metres (25 ft) wide carriageways, permitting driving speeds of up to 100 km/h. The tunnel features an autonomous drainage system channeling water accumulating due to tunnel cleaning, as well as any seeping water, firefighting and accidents. The tunnel is equipped with variable traffic signs in order to ensure enhanced safety of the traffic, regulated from traffic control centres along the A1 motorway. Electronic equipment of the tunnel allows use of two VHF radio frequencies (HR1 at 102.3 MHz and HR2 at 97.5 MHz) as well as cell phones. Electrical power is supplied to the tunnel via one 35 kV switching station at each end of the tunnel and 8 distribution switching stations in the tunnel itself. A backup electrical power supply is also provided to ensure continuous operation of the tunnel.
The tunnel has been executed using New Austrian Tunnelling method, by means of drilling and explosive blasting. Numerous caves, caverns and other speleological structures were found during constructions, but all of those were addressed successfully. 1,137 metres (3,730 ft) of underground channels were found during construction, including a hall measuring 148 metres (486 ft) by 53 metres (174 ft) by 62 metres (203 ft), found at chainage 200+525. Some of the structures are of considerable length, as they appear to be connected to the surface - as inferred by presence of bats. The speleological structures encountered during the construction presented problems to construction of the tunnel, but they have been successfully preserved as natural phenomena.
Traffic volume
Traffic is regularly counted and reported by Hrvatske autoceste, operator of the bridge and the A1 motorway where the bridge is located, and published by Hrvatske ceste. Substantial variations between annual (AADT) and summer (ASDT) traffic volumes are attributed to the fact that the bridge carries substantial tourist traffic to the Dalmatian Adriatic resorts. The traffic count is performed using analysis of motorway toll ticket sales.