Northern Territory Consolidated Regulations Northern Territory Consolidated Regulations(1) A combination must not be over:
(a) for a B-double – 25 metres long; and
(b) for a road train – 53.5 metres long; and
(c) for a combination, except a road train, designed to carry vehicles on 2 or more partly or completely overlapping decks – 25 metres long; and
(d) for another combination – 19 metres long.
(2) In a B-double built to carry cattle, sheep, pigs or horses, the 2 semi-trailers must not have over 18.8 metres of their combined length available for the carriage of animals.
(3) For subrule (2), the length available for the carriage of animals on a trailer is measured from the inside of the front wall or door of the trailer to the inside of the rear wall or door of the trailer, with any intervening partitions disregarded.