The traffic capacities of small roundabouts were investigated so that they could be compared with other types of junction, and that the possibilities may be considered of improving them. Details are given of the data collection procedure, as well as of the analysis and results. Traffic counts were made and converted into vehicles per hour and p.c.u. per hour using the p.v.u. equivalents for roundabouts. The investigation showed that where 2 lane approaches existed, they were not used effectively and that 2 traffic lanes can be accommodated inside an inscribed circle of 35 meters diameter with a central island of 10 meters diameter, the inside lane being 7.5 meters. Conclusions based on the study are presented.

  • Supplemental Notes:
    • Presented at Seminar X (Road Design 1: General Topics) of the PTRC Summer Annual Meeting, Warwick University, England, 8-12 July 1974.
  • Corporate Authors:

    Planning and Transport Res and Computation Co Ltd

    167 Oxford Street
    London W1R 1AH,   England 
  • Authors:
    • Grant, E
  • Publication Date: 1974-7

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00096287
  • Record Type: Publication
  • Report/Paper Numbers: PTRC/P/108
  • Files: TRIS
  • Created Date: Sep 10 1975 12:00AM