VEHICLE SPEEDS AND PATHS AT RURAL DIAMOND ROUNDABOUT MOTORWAY INTERCHANGES

Two flyunder and one flyover versions of this type of interchange were subjected to detailed study by the University of Nottingham. Flow conditions corresponded to level of service a. With the low convergence angles and long direct taper acceleration lanes provided, most of the acceleration to merging speed occurred on the slip road, leaving the acceleration lane to provide only the necessary merging distance. Similarly exiting vehicles largely postponed deceleration until they had entered the slip road. Both these characteristics were particularly pronounced in the flyunder designs where visibility is improved and gravity assists speed changes. (A). /TRRL/

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  • Corporate Authors:

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • Ackroyd, L W
    • Madden, A J
  • Publication Date: 1975-5

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00127776
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Dec 3 1975 12:00AM