The M25 London orbital motorway, which now carries 14 per cent of all motorway traffic in Britain, is to be widened from dual three lane to dual four lanes. Short term measures, including the narrowing of existing lanes will be considered. One method recommended is to use the hard shoulder as a running lane, providing new lay-bys at frequent intervals. An alternative is to form a narrow, car-only outside lane within the existing boundaries, keeping the other three lanes and hard shoulder but with reduced widths. Other measures being considered are lighting, variable message signs activated by automatic incident detection, improved access and access control at junctions. Ramp metering at access points, shown to produce a three per cent improvement in flow, is to be investigated. The Department of Transport has rejected the proposed introduction of a 50 mile/h limit which would require legislation, although narrow lanes would require this limit. It is hoped that sections where widening can be accomplished with the existing boundary will be completed within four years. (TRRL)

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  • Corporate Authors:

    D.R. Publications Limited

    Faversham House, 111 St James Road
    Croydon, Surrey CR9 2TH,   England 
  • Publication Date: 1990-12


  • English

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Filing Info

  • Accession Number: 00617630
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Nov 30 1991 12:00AM