Which Public Transit Routing Alternatives are Worth Calculating? A Transit Lines Filtering Algorithm to Generate Alternatives

This paper proposes a transit alternatives generation algorithm based on the Connection Scan routing Algorithm (CSA). The algorithm generates alternatives by filtering, in multiple rounds, combinations of lines that were used in the shortest path (earliest arrival time) and in previous rounds. The algorithm is able to generate almost all feasible alternatives but needs constraints in order to increase its performance. To select the constraints, declared route choice data from the Montreal regional household travel survey of 2013 was analyzed. The declared routes were matched with the generated alternatives and a comparison between the chosen alternative and the shortest path was made. The main finding is that 54% of all the declared route choices are also the shortest path. Besides, the 95th percentiles of the ratios of declared route to shortest path travel times are used as time thresholds: the algorithm stops when all the alternatives generated at the previous round have travel times greater than the ratio for a specific age group or a specific activity. In all the data, at least 95% of the declared route choices have travel times less than 2.3 times the duration of the shortest path. Moreover, trips between 15 and 120 minutes have 95th percentiles ratios under 1.7. Also, since more than 95% of all declared routes have a maximum of one more transfer than the shortest path, using this value as the limit in the calculations can further enhance the algorithm performance.

  • Supplemental Notes:
    • This paper was sponsored by TRB committee AP025 Standing Committee on Public Transportation Planning and Development.
  • Corporate Authors:

    Transportation Research Board

  • Authors:
    • Bourbonnais, Pierre-Leo
    • Verreault, Hubert
    • Morency, Catherine
  • Conference:
  • Date: 2019


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; References;
  • Pagination: 7p

Subject/Index Terms

Filing Info

  • Accession Number: 01697515
  • Record Type: Publication
  • Report/Paper Numbers: 19-04586
  • Files: TRIS, TRB, ATRI
  • Created Date: Dec 7 2018 9:29AM