A number of techniques have been simulated that give buses priority over other traffic by preempting traffic signals as buses approach an intersection. An unconditional preemption algorithm, in which the signal is changed to green and held green as long as the bus is within 200 feet upstream from the intersection, provides 25 percent travel time benefit to buses. However, the delay to cross-street traffic can be extreme, particularly at short bus headways. An algorithm limiting the preemption to a maximum of 10 seconds provides 20 percent bus travel time improvement with only 7 percent cross-street travel time increase, even at half-minute headways. The large number of simulation runs performed has revealed factors important to the operation of such a bus priority system. Bus stops on the far-side of intersections are far superior to near-side buss stops. Buses with frequent stops have greater potential for improvement than express buses, especially if existing signal coordination is good. Instrumenting all signalized intersections is particularly important in improving express bus travel time. /UMTA/

  • Corporate Authors:

    Mitre Corporation

    Westgate Research Park
    McLean, VA  United States  22101

    Urban Mass Transportation Administration

    400 7th Street, SW
    Washington, DC  United States  20590
  • Authors:
    • Ludwick Jr, J C
  • Publication Date: 1976-2

Media Info

  • Pagination: 34 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00132995
  • Record Type: Publication
  • Source Agency: Urban Mass Transportation Administration
  • Report/Paper Numbers: UMTA-VA-06-0026-76-1Final Rpt.
  • Contract Numbers: DOT-UT-50016
  • Files: TRIS, USDOT
  • Created Date: Jun 5 1976 12:00AM