The tunnel was constructed from 1968 to 1975 with three bores, containing a total of six
autobahn lanes serving the city of
Hamburg. On 10 January 1975 the
Chancellor of Germany,
Helmut Schmidt, opened the Elbe Tunnel. The tunnel was constructed with a capacity for 65,000 cars daily. (to the south east) In 1989 concrete tank barriers were constructed on the three south entrances. In war times these barriers would have been exploded out of their resting places. The barriers were removed in 2000 during construction of the 4th bore.
Widening To meet the demands of increasing traffic, on 27 October 2002 a fourth bore was opened with two more lanes. The total cost for this expansion amounted 550 million euros. It had been drilled through the ground by the then world's largest
tunnel boring machine (TBM), which had a front plate 14.65 m (48 ft 1 in) in diameter. The machine's name was Trude, a short form of the name
Gertrud, and an acronym for
Tief runter unter die Elbe (deep down under the Elbe). The
European Space Agency had helped in engineering aspects of the tunnel project for the tunnel boring machine. The centre bores carry
reversible lanes which switch direction in anticipation of commuter flows, similar to those of
Caldecott Tunnel in
Oakland, California. For example, more lanes are available for the morning commute into the city center in the northward direction
Flensburg, and more in the southbound direction of
Hanover for traffic leaving the city in the evening. . ==Vehicle height control==