SIG-NABOUT. THE DEVELOPMENT AND TRIAL OF A NOVEL JUNCTION DESIGN

The idea for this new type of junction was first suggested by Kimber,RM and Semmens,MC in 1982 (see IRRD 266722). The junction was later named a "SIG-NABOUT" because it combines the features of a SIGnalled junction and a roundABOUT. A SIG-NABOUT is a large signalised crossroads, but with two important differences: (1) the approaches have a significant degree of local flaring, with short merge areas on the exits; and (2) there is a large central area divided into four reservoirs for storing those turning right, who are primarily intended to complete their turn during the interstage period following the associated green. A junction of this type was tested by the Transport Research Laboratory (TRL) on its test track, with promising results. Simulation techniques also gave an indication of the capacity which could be achieved from such junctions. A public road trial was carried out at the Sefton junction (near Liverpool), which was converted from a traditional roundabout in 1993. TRL conducted a before and after study in early July 1992, and June 1993, the results of which are reported here.

• Corporate Authors:

  TRL

  Crowthorne House, Nine Mile Ride
  Wokingham, Berkshire  United Kingdom  RG40 3GA
• Authors:
  • WEBB, P J
• Publication Date: 1994

Language

• English

Media Info

• Features: References;
• Pagination: 5 p.

Subject/Index Terms

• TRT Terms: Design; Highway capacity; Intersections; Layout; Traffic delays; Traffic flow; Traffic signals
• Subject Areas: Design; Highways;

Filing Info

• Accession Number: 00662196
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, ATRI
• Created Date: Jul 28 1994 12:00AM