# Directive 2004/54/EC of the European Parliament and of the Council of 29 April 2004 on minimum safety requirements for tunnels in the trans-European road network, Division 2.1.3

Extent: E+W+S+N.I.

With the exception of the emergency lane, the same number of lanes shall be maintained inside and outside the tunnel. Any change in the number of lanes shall occur at a sufficient distance in front of the tunnel portal; this distance shall be at least the distance covered in 10 seconds by a vehicle travelling at the speed limit. When geographic circumstances prevent this, additional and/or reinforced measures shall be taken to enhance safety.

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Source: https://www.legislation.gov.uk/eudr/2004/54/annex/I/division/2.1.3 (the official version)
Page: https://openlegislation.uk/eu-directive-2004-54/annex-I/division-2.1.3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.