After studying all the 3 variants, the variant with a shorter tunnel was selected, mainly for environmental reasons. The tunnel from that variant is 1440 m long for the western (right) tube, and 1415 m for the eastern (left) tube. The covered parts near the building of the Slovak Academy of Sciences are 206 m and 216 m long, respectively. The width of the road is 7.5 m, and features 1 m wide hard shoulders. The average gradient in the tunnel is 2.34%. The maximum allowed speed will be 80 kilometres per hour (50 mph). The tunnels were built using New Austrian Tunnelling method (NATM).