THE ROADWAY ASSIGNMENT COMPARISON PROGRAM, RDSTRC

It is sometimes necessary for the transportation planner to assess the implication of a change in tree building assumptions within the modelling process e.g. the effect of building trees on the basis of time rather than distance. How stable is a particular assignment under these circumstances? Other factors such as a change in the time needed to traverse a length of road may also be involved. The assessment of the influence of such changes is currently often the result of arduous manual techniques or somewhat limited computer applications. A problem applying to both of these approaches concerns the need to completely examine the model output in fine detail before it is possible to determine whether or not major changes have been induced. This paper presents a test case involving sample output from the run of program RDSTRC. RDSTRC will perform an assignment comparison on two roadway loaded networks and produce user controlled diagnostics aimed at assisting the user to readily identify not only the degree but also the location of changing journey patterns from one assignment to another. It has been designed to avoid the unnecessary use of computer time by means of the provision of user controlled progressive levels of detail. Thus an overall impression of assignment stability may be obtained prior to producing full comparison printouts which could prove redundant if there were negligible or even massive variation. The paper demonstrates how an alteration of the trees indicates initially a significant change in the assignment leading to further examination via the subsequent options. This increased detail includes tables and histograms summarizing the major features and reference is made to the "change" matrix. This matrix may be output from the program and contains trip information relating only to journeys which change route between assignments. The possibilities for further use of this matrix is demonstrated. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0860501124
• Supplemental Notes:
  • This paper was presented at Seminar, Developing Countires, held at the PTRC Annual Summer Meeting, University of Warwick, England, 4-7 July, 1983.
• Corporate Authors:

  PTRC Education and Research Services Limited

  110 Strand
  London WC2,   England 
• Authors:
  • MARTIN, I W
  • DOUGLAS, J V
• Conference:
  • Planning & Transport Res & Comp, Sum Ann Mtg, Proc
• Publication Date: 1983

Media Info

• Features: Figures;
• Pagination: p. 93-100

Subject/Index Terms

• TRT Terms: Computer programs; Conferences; Histograms; Information processing; Itinerary; Mathematical models; Networks; Planning; Stability (Mechanics); Time; Traffic assignment; Transportation; Transportation planning; Travel; Trees (Mathematics)
• Uncontrolled Terms: Change; Modifications; Transportation networks
• ITRD Terms: 8525: Conference; 699: Itinerary; 698: Journey; 6473: Mathematical model; 9048: Modification; 1054: Network (traffic); 143: Planning; 8645: Software; 5414: Time; 679: Traffic assignment; 1155: Transport
• Subject Areas: Operations and Traffic Management; Planning and Forecasting; Transportation (General); I71: Traffic Theory;

Filing Info

• Accession Number: 00382851
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• ISBN: 0-86050-112-4
• Report/Paper Numbers: Volume P240
• Files: ITRD, TRIS
• Created Date: May 30 1984 12:00AM