[3] Construction of Veliki Gložac Tunnel was started by Spie Batignolles and Mediteran Union Tunel.

Since axes of the two are merely 25 metres (82 ft) apart, and an oil pipeline runs nearby, blasting entailed special precautions.

Initial blast yield was lower and then gradually increased in order to achieve optimum results while maintaining safety.

Finally, noise and oscillations of the first tunnel tube and the oil pipeline were constantly monitored to detect any sign of damage.

[7] Traffic is regularly counted and reported by Autocesta Rijeka–Zagreb, operator of the A6 motorway and the tunnel, and published by Hrvatske ceste.