ACCOMMODATING TRANSIT IN TRANSYT

Although the TRANSYT traffic model simulates transit vehicles in mixed traffic operation, it does not adequately consider the effects of bus or streetcar stops on the traveled roadway near signalized intersections. Specifically, it assumes that transit vehicles loading and unloading passengers do not delay other vehicles. This reduces the validity of TRANSYT evaluations for cycles in which buses stop at or very near signalized intersections. The overall TRANSYT predictions and optimizations for an average cycle will be seriously threatened if total bus or streetcar dwell time per hour is significant. Therefore, an alternative type of network formulation, which uses dummy nodes and dummy links with appropriate link costs, is proposed for modeling the effects of transit stops on intersection performance. Although it requires one dummy node and four or six dummy links for each transit stop that delays traffic, it significantly improves TRANSYT's realism for such operations. Parameters for these dummy links have been tested over a wide range, and a set of operational values is recommended. Flow profiles illustrating the need for the effects of the recommended formulation are presented in this paper.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1988/1181/1181-008.pdf
• Record URL:
  https://scholar.google.com/scholar_lookup?title=ACCOMMODATING+TRANSIT+IN+TRANSYT&author=S.+Yager&publication_year=1988
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309047501
• Supplemental Notes:
  • This paper appears in Transportation Research Record No. 1181, Urban Traffic Systems and Parking. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Yager, Sam
• Publication Date: 1988

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 68-76
• Monograph Title: Urban traffic systems and parking
• Serial:
  • Transportation Research Record
  • Issue Number: 1181
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Bus stops; Computer programs; Dwell time; Links (Networks); Nodes (Networks); Optimization; Signalized intersections; Stopping; Streetcars; Traffic delays; Traffic flow; Traffic signal timing
• Uncontrolled Terms: Links; Modifications
• Old TRIS Terms: Nodes
• Subject Areas: Highways; Operations and Traffic Management; Public Transportation; Railroads; I73: Traffic Control;

Filing Info

• Accession Number: 00486049
• Record Type: Publication
• ISBN: 0309047501
• Files: TRIS, TRB, ATRI
• Created Date: Aug 31 1989 12:00AM