translate English to French: The text deals with a categorization of tunnels in road transport.  Multimodal, part 2 deals with the classification of substances and it would be very confusing to include tunnel provisions for road transport in this part.
Étant donné que la partie 2 porte sur la classification des matières, l'inclusion de dispositions relatives aux tunnels routiers dans cette partie risquerait de créer une grande confusion.