LEFT TURN SLIP LANE STUDY. NEW ZEALAND ROADING SYMPOSIUM 1987. VOLUME 3

The left turn slip lane study, carried out in 1985/86 by the authors of this paper for the Road Construction Authority, Victoria, was a review of the operation and safety of a number of alternative design treatments for left turn slip lanes. The study found that the standard left turn slip lane treatment which provides a left hand curve and a merge taper was poorly utilised. Most left turning drivers were observed not to use the merge taper, instead preferring to stop and give way before entering the through traffic stream and the low angle at which the vehicles stopped made vision difficult. Two alternative left turn slip lane treatments were found to provide for improved operation. One treatment, the high entry angle slip lane, provides a higher angle of entry to enable ease of vision for left turning drivers to select a gap in the through traffic stream. The second treatment, the free flow slip lane where the standard treatment is modified to provide an acceleration lane prior to the merge taper, was observed to operate satisfactorily and to be suitable for higher left turn volume sites. This paper discusses the study, its findings and the subsequent adoption by the Road Construction Authority, Victoria of the high entry angle left turn slip lane and the free flow slip lane as the standard slip lane treatments. For the covering abstract of the symposium see IRRD 810782. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0477071562
• Corporate Authors:

  National Roads Board, New Zealand

  P.O. Box 12-041
  Wellington,   New Zealand 
• Authors:
  • Aitken, R N
  • Milvydas, A J
  • Barton, A L
• Publication Date: 1987

Media Info

• Features: References;
• Pagination: p. 607-614
• Serial:
  • Publication of: UNITED NATIONS
  • Publisher: United Nations
  • ISSN: 0252-4392

Subject/Index Terms

• TRT Terms: Acceleration lanes; Alternatives analysis; Angularity; Conferences; Design; Layout; Merging area
• Old TRIS Terms: Angles, geometry
• ITRD Terms: 5405: Acceleration; 435: Access road; 6427: Angle; 8006: Australia; 8525: Conference; 426: Entrance; 2885: Layout; 2827: Traffic lane; 676: Traffic survey; 1836: Turning; 9084: Use
• Subject Areas: Design; Highways;

Filing Info

• Accession Number: 00476419
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• ISBN: 0-477-07156-2
• Files: ITRD, TRIS
• Created Date: Sep 30 1988 12:00AM