390.The general law on road traffic regulation, consolidated in the Road Traffic Regulation Act 1984 ("RTRA 1984"), is varied considerably in its application to London.  The Local Government Act 1985 (which abolished the Greater London Council and the metropolitan county councils) transferred most of the traffic authority functions of the GLC (many of which extended to all roads in Greater London except trunk roads) to the London borough councils.
391.Part II of the Road Traffic Act 1991 made further provision about traffic in London, by creating a network of priority ("red") routes and a new statutory office of Traffic Director for London to carry out the red route programme.  The Act also provided for a separate system of enforcing parking restrictions in London without the sanction of the criminal law.
392.Traffic regulation law, unlike highways law, is entirely a creature of statute. It enables traffic authorities - in this case TfL – to regulate the way in which the public use highways and other roads to which the public has access. It is principally concerned with the regulation of vehicles, whether moving or stationary, but also extends to all other types of traffic.
Commentary on Sections Part Iv: Transport Chapter Xiv: Road Traffic