# 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 1.1.2: The following parameters shall be taken into account:

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

tunnel length,
number of tubes,
number of lanes,
cross-sectional geometry,
vertical and horizontal alignment,
type of construction,
uni-directional or bi-directional traffic,
traffic volume per tube (including its time distribution),
risk of congestion (daily or seasonal),
access time for the emergency services,
presence and percentage of heavy goods vehicles,
presence, percentage and type of dangerous goods traffic,
characteristics of the access roads,
lane width,
speed considerations,
geographical and meteorological environment.

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Source: https://www.legislation.gov.uk/eudr/2004/54/annex/I/division/1.1.2 (the official version)
Page: https://openlegislation.uk/eu-directive-2004-54/annex-I/division-1.1.2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.