3In section 12 of the Airports Authority Act 1965 (control of road traffic within British Airports Authority aerodromes) in subsection (3) (order may exempt particular roads from application of road traffic enactments) for the words from " particular roads" to the end of the subsection there shall be substituted the words " such roads or lengths of roads to which the public does not have access as the Authority may for the time being identify as being so exempted by means of a sign of a type or character specified in the order ".