A Guidebook on Improving Bus Transit Reliability

Bus service unreliability is a key quality-of-service issue for passengers and an important driver of bus operations costs for transit agencies. From the passenger point of view, unreliable service means that customers must allow extra time for their trip to make sure of arriving at their destination by a particular time--time that could have been used more productively in other ways. Although a typical rule of thumb is that passengers perceive wait time as being twice as onerous as in-vehicle time, recent research indicates that transit passengers perceive unexpected wait time as being 3 to 5 times as onerous as in-vehicle time. In contrast, automobile travelers value travel time unreliability (i.e., unexpected delay) at approximately the same level that they value travel time, suggesting that transit service is at a competitive disadvantage with the automobile with respect to unreliable travel times. From the transit agency point of view, travel time unreliability impacts a route's cycle time and, ultimately, operating cost. In a best-case scenario, the reduced cycle time resulting from reduced travel time variability allows a bus to be removed from a route while maintaining the scheduled headway. Conversely, if reliability issues are not addressed, a transit agency eventually needs to add buses to a route (increasing costs) or decrease bus frequency (risking a vicious cycle of ridership decline and/or worsening unreliability). The Transit Capacity and Quality of Service Manual (TCQSM) lists the following factors as influencing reliability: traffic conditions and road construction, vehicle and maintenance quality, vehicle and staff availability, transit preferential treatments, schedule achievability, evenness of passenger demand, variations in bus operator experience, wheelchair lift and ramp usage, route length and the number of stops, and operations control strategies. Weather--particularly snow and extreme temperatures--also plays a role. These factors have been addressed individually by research to some degree--for example, operations control strategies, scheduling, bus operator experience, route length, and applications of Automatic Vehicle Location Technology--but no comprehensive research has yet been conducted that addresses all these factors in combination. Transit operators require guidance on measuring and valuing reliability from the passenger point of view; the effects of potential operational, technological, and physical measures to improve reliability in particular situations; and the potential benefits and costs of those measures. Accurately estimating the benefits of reliability-improvement measures is necessary for bus operators, both to gain the acceptance of roadway-owning agencies to implement certain treatments (e.g., bus stop relocation, traffic signal priority, queue jumps) and to compete for scarce transportation funds to implement improvements on a large scale (e.g., along an entire route or throughout a city). A guidebook on improving bus transit reliability would identify cost-effective techniques for improving bus reliability, thereby helping to improve ridership and provide more cost-efficient bus service. The objectives of this research are to (1) develop a toolbox of measures to identify, diagnose, and treat bus reliability issues; (2) quantify the benefits and costs of each measure on reliability; and (3) prepare a comprehensive guidebook for bus operators to use to improve their service reliability.


  • English


  • Status: Proposed
  • Contract Numbers:

    Project A-42

  • Sponsor Organizations:

    Federal Transit Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    Transit Cooperative Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC    20001
  • Project Managers:

    Parker, Stephan

  • Start Date: 20150127
  • Expected Completion Date: 0
  • Actual Completion Date: 0
  • Source Data: RiP Project 38985

Subject/Index Terms

Filing Info

  • Accession Number: 01551875
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project A-42
  • Files: TRB, RiP
  • Created Date: Jan 28 2015 1:00AM