6.—(1) Subject to paragraph (2), where the major works consist of or include major bridge works, allowable costs shall be so calculated that the undertaker is not liable for costs in respect of the provision of–
(a)adequate space in the structure of the bridge; or
(b)sufficient strength in the bridge,
to accommodate the undertaker’s apparatus in the bridge.
(2) paragraph (1) does not apply to the costs of–
(a)any ducts, pipe bays, hangers or other provision for housing or supporting the undertaker’s apparatus within the structure of the bridge;
(b)the provision of adequate space or adequate strength to accommodate apparatus installed in the bridge after the execution of such major works other than the installation, replacement or modification (not involving enlargement) of apparatus previously installed in the bridge before the execution of those works.
(3) In calculating an undertaker’s allowable costs there shall be disallowed costs incurred in respect of apparatus placed in the road after the authority has given to the undertaker–
(a)in the case of major works consisting of major bridge works comprising a replacement of the bridge, not more than 10 years;
(b)in the case of any other major works, not more than 5 years,
notice of their intention to execute the major works.