Creating dual carriageways where there is no physical separation between the lanes is mapping for the renderer. Please do not do this. If TomTom wish to represent unsegregated traffic lanes separately, that should be accomplished in TomTom's own rendering and routing software, not OSM-Carto.

See https://wiki.openstreetmap.org/wiki/Dual_carriageway :
"Roads are not to be mapped as dual carriageways if the two directions are only separated by paint. This includes single or multiple painted centre lines, hatched areas, channelized turn lanes, two-way turn lanes,
by flush medians, or by any other means that is not a physical barrier to vehicles."

Fixed in https://www.openstreetmap.org/changeset/163278990