Signal Controlled Roundabouts - A New Guidance Paper

This paper describes how the Local Transport Note (LTN) 1/09 is a long-awaited publication bringing together current thinking on the design and operation of signalized roundabouts. For the first time, traffic engineers will be able to access all the necessary information and advice related to up-to-date best practice, much of it unpublished elsewhere, in a single document. It is anticipated that the LTN 1/09 will lead to more consistency and efficiency in signalized roundabout design. Signalized roundabouts are an increasingly popular form of junction control. The first experiments with adding signals to selected arms of existing roundabouts (at peak hours only) were carried out in the late 1950s but it was not until the early 1990s that the use of signals at roundabouts really began to grow. Since then, analysis and control techniques have developed rapidly along with increased requirements for the consideration of pedestrians and cyclists. As a consequence, the design of signalized roundabouts has become very complex and is now a specialized field in its own right. Even so, signalized roundabouts are not so common that the average competent traffic engineer will have had significant experience in their design. Wide experience of the design of both roundabouts and complex traffic signal junctions is not in itself enough to guarantee that an engineer will be able to produce an optimum design for a signalized roundabout. Unfortunately there are many examples in place of signalized roundabouts which are not as well designed as they could be. Layouts and the control strategies are less than optimum and in many cases there are aspects which do not comply with national regulations. A new guidance note has been prepared and is now being published by the Department for Transport as LTN 1/09 “Signalized Roundabouts” to help traffic engineers through the design process. It aims to complement rather than to replace existing published advice. The development of this guidance note is part of a larger project carried out by the Department of Transport. The key aims were to: investigate current practice; and identify factors which affect safety, efficiency and capacity of signalized roundabouts. This has culminated in the preparation of a guidance document for practitioners. The guidance note has drawn from numerous previous studies and reports and takes account of published advice notes and standards as well as referencing relevant regulations. The draft has been extensively commented on by leading practitioners and interest groups and it is hoped that the resulting document presents a comprehensive picture of current best practice in the design of signalized roundabouts.

• Record URL:
  • https://aetransport.org/past-etc-papers/conference-papers-pre-2009/conference-papers-2009
• Corporate Authors:

  Association for European Transport (AET)

  1 Vernon Mews, Vernon Street, West Kensington
  London W14 0RL,    
• Authors:
  • Ridding, Colin
  • Phull, Suku
• Conference:
  • European Transport Conference, 2009
  • Location: Leiden Leeuwenhorst Conference Centre , Netherlands
  • Date: 2009-10-5 to 2009-10-7
• Publication Date: 2009

Language

• English

Media Info

• Media Type: Web
• Features: Photos; References;
• Pagination: 8p
• Monograph Title: European Transport Conference, 2009 Proceedings

Subject/Index Terms

• TRT Terms: Best practices; Guidelines; Highway design; Highway safety; Highway traffic control; Roundabouts; Signalized intersections; Traffic control devices; Traffic engineering
• Geographic Terms: United Kingdom
• Subject Areas: Highways; Operations and Traffic Management; I73: Traffic Control;

Filing Info

• Accession Number: 01349543
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 10 2011 10:43AM