System-Specific Spare Bus Ratios Update (2014)

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4 The paper includes an overview of training/learning meth- odologies; return on investment (ROI) benchmarking and performance monitoring; and guidance for measuring training program performance, including a framework for assessing the “bottom line” business impact of effective training programs. Some of the key performance metrics identified that could be linked to effective training programs included mean dis- tance between failures, repeat failures, schedule adherence, maintenance cost per mile, and the bus spare ratio. The paper established a strong link between improved maintenance training and the number of spare buses needed to support the transit revenue fleet, pointing out that “one indication of poor maintenance resulting from untrained workers is the need to have a larger ratio of spare buses. The extra buses are needed to account for vehicles that are less reliable and therefore more frequently in the depot, and for untrained workers who typically require more time to diagnose and repair faults.” The paper then offered a methodology with which to esti- mate the ROI, taking into account training program costs and the cumulative financial benefits received—including, but not limited to, savings from a lower bus spare ratio. As an example, the five-level methodology was applied to Penn- sylvania’s Keystone Transit Partnership experiment at the Southeast Pennsylvania Transportation Authority (SEPTA) where the ROI was convincingly demonstrated. Minkoff, M., Bus Fleet Management in an Era of Increas- ing Technical Complexity: Analysis of Bus Fleet Spare Ratios, TCRP Project J-06, Task 73, Transportation Research Board, Washington, D.C., 2009. This research focused on the significant changes that had taken place over the years affecting bus fleet characteristics and management. The paper examined how the spare bus ratio, as defined by FTA (and previously, the Urban Mass Transportation Administration) is applied in the field. The research focused on answering critical questions related to the impact of several factors on transit agencies’ abilities to oper- ate within the 20% fleet-wide spare ratio standard established by the FTA. These factors were increased fleet mix diversity; the introduction of alternative fuels and energy technologies; the implementation of advanced on-board technologies; the profile of transit service types offered to the public (and the interoperability of buses between service types); workforce constraints; and whether a 20% fleet-wide spare ratio was The literature review related to bus fleet spare ratios gener- ated only eight documents published between 1988 and 2012, which will be discussed in reverse chronological order. LITERATURE REVIEWED Li, T., A. Gan, and F. Cevallos, “Characteristics of Bus Transit Vehicles in the United States: How They Have Changed Over a Quarter Century,” presented at the 53rd Annual Transporta- tion Research Forum, Tampa, Fla., Mar. 15–17, 2012. Using data drawn from the National Transit Database (NTD), this research paper looked at the national trends of major characteristics associated with bus revenue vehicles. The characteristics examined included the number of vehi- cles transit fleets, the spare ratios, average age of the fleet, average capacity, Americans with Disability Act (ADA) accessibility, vehicle reliability, and vehicle operations and maintenance costs. According to this research, spare ratios have consistently exceeded the maximum of 20%, as suggested by the FTA; buses operated by contractors tended to be significantly newer than those directly operated by transit agencies (although the gap has narrowed); vehicles operated directly by transit agen- cies tended to have greater seating and standing capacities than those operated by contractors; and by 2006, nearly all bus vehicles were ADA-compliant (and increasingly, vehicles with lifts were converted to vehicles with ramps/low-floors). Among the most significant findings were that the reliability of buses, in terms of the number of mechanical failures per million revenue vehicle-miles, had significantly improved over the years; and that contractors spent less on average than transit agencies in operating and maintaining their vehicles. Schiavone, J. and X. Wang, Method and Processes for Tran- sit Training Metrics and Return on Investment, Transportation Learning Center, Silver Spring, Md., 2011. This white paper highlighted the critical importance of robust maintenance training programs in the transit indus- try and quantifying the benefits. The report described an approach to quantitatively evaluating the benefits and value of training programs, explaining that most transit agencies lacked the ability to measure training effectiveness or to use those results to advocate for additional expanded training. chapter two LITERATURE REVIEW

5 an appropriate benchmark. The research included an analy- sis of National Transit Database information, an on-line sur- vey, three case examples, and outreach to the FTA. The work offered a set of recommendations and conclusions for consid- eration under the APTA standards program, including items to consider in developing a recommended practice for calculat- ing bus fleet spare ratios. These included the exclusion of cer- tain vehicle types from the calculation of the fleet-wide spare ratio, and recognized variations in spare bus flexibility needed for different bus fleet sizes: those with fewer than 50 vehi- cles, those with 50 to 250 vehicles, and those with more than 250 vehicles. Pierce J. and E. Moser, TCRP Synthesis 11: System- Specific Spare Bus Ratios, Transportation Research Board, National Research Council, Washington, D.C., 1995. This TCRP synthesis documented the critical site-specific variables affecting the number of spare vehicles that bus systems need to maintain and support peak service require- ments. The project involved transit managers at a cross-section of agencies of various size and geographic location who responded to a detailed questionnaire and follow-up interviews. This synthesis concluded that although respondents generally acknowledged that right-sizing the fleet improves operations and lowers cost, many reported difficulties in achieving and consistently maintaining the FTA-prescribed 20% spare ratio. The consensus was that more flexibility was required in deter- mining the actual number of vehicles needed to accommodate the different operating environments and service requirements unique to each transit system. Respondents to the survey urged that more emphasis be placed on developing improved bus maintenance techniques that would assist them in minimizing down time and improving vehicle availability, ultimately lead- ing to reduced spare vehicles and lower labor and materials costs. This synthesis found that many agencies have been suc- cessful in limiting their spare vehicle fleets as a result of a corporate philosophy of maintaining a “lean fleet”; strong pre- ventive maintenance (PM) programs; regular procurement of new vehicles; effective use of advanced technology for critical maintenance programs; and managing the workforce to create a more cooperative environment. Branch, P., National Bus Spare Ratio Study, Federal Tran- sit Administration, Washington, D.C., 1993. This FTA study examined national bus spare ratios across all fleet sizes, except those FTA grantees operating fewer than 50 vehicles. This work statistically analyzed spare ratio percentages as a whole and by fleet size groupings over a five-year period between 1985 and 1990. In summary, the study found that two-thirds of all transit agencies sampled achieved a spare ratio of 25% or less, and 79% achieved a 30% spare ratio or less. This FTA work concluded that the transit industry as a whole has worked toward achieving the FTA’s goal of a 20% fleet-wide spare ratio. Jaraiedi, M. and W. Iskander, “Statistical Evaluation of Spare Ratio in Transit Rolling Stock,” Transportation Research Record 1221, Transportation Research Board, National Research Council, Washington, D.C., 1989, pp. 88–90. In this research work, statistical techniques were used to analyze the relationships between variations in spare ratio and characteristics of bus transit properties. Section 15 (the pre- cursor to the NTD) data for 1984 were used for this analysis. The study analyzed 14 important variables that affected bus spare ratios; and classified transit agency fleets into groups with high, average, or low spare ratios. The study found that there is a significantly lower average total number of road calls per vehicle hour for properties that have a low spare ratio than there is for those that have medium or high ratios. Mechanical and total road calls per vehicle-mile exhibit simi- lar patterns. The study concluded that the percentage of fed- eral assistance to total revenue has a lower average in systems with lower spare ratios. The authors further concluded that properties with high spare ratios rely on federal assistance more than have those that have low spare ratios. Iskander, W., M. Jaraiedi, and S. Niaki, “Simulation Study to Evaluate Spare Ratios in Bus Transit Systems,” Trans- portation Research Record 1221, Transportation Research Board, National Research Council, Washington, D.C., 1989, pp. 77–87. This work involved the development of a simulation model that could be used to assess the appropriate spare ratio level needed to maintain a desirable level of service dependability. The model evaluated the effects of the rates of bus mechanical failures, repair time, and other characteristics on the spare ratio and overall performance of the transit system. The model was validated and used to simulate the bus operations of an exist- ing transit system. Iskander, W. and M. Jaraiedi, Evaluation of the Spare Ratio Concept in the Management of Transit Rolling Stock, Urban Mass Transportation Administration, Washington, D.C., 1988. This work was the basis of the last two publications described, investigating the issue of spare vehicles and spare ratios in transit bus fleets. Statistical techniques were used to investigate the relationship between variations in the spare ratio and characteristics of bus transit systems. A simula- tion model was also developed in order to analyze the effect of different variables and characteristics on the choice of a proper value for a fleet’s spare ratio. Procedures were devel- oped to determine optimal strategies for bus acquisition and retirement, and of allocation of funds to purchase new equipment in order to maintain a desirable level of service dependability. The model was validated and used to study bus operations of the Kanawha Valley Regional Transporta- tion Authority in Charleston, West Virginia.

6 SUMMARY This literature review underscored the limited research that has been performed on this topic over the last 25 years, despite the extensive evolution of transit bus agencies’ oper- ation and maintenance policies. Li et al. (2012) provided an excellent context for review- ing and understanding spare bus-related issues with their analysis of the significant changes in transit fleet charac- teristics over the last 25 years. Schiavone and Wang (2011) provided insights and methodologies for improving the state of maintenance training at transit agencies, making a case for increased expenditures on maintenance training as a posi- tive ROI. Pierce and Moser (1995) and Minkoff (2009) explored the wide variation among transit agency bus fleets, operating environments, service characteristics, and maintenance pro- gram; and the need for flexibility in determining the appro- priate number of spare buses required. Branch (1993) provided a thorough statistical analysis, documenting bus fleet spare ratio performance among sampled transit agencies over a six-year period (1985–1990) and tran- sit industry compliance with the FTA 20% guideline. While quantitatively explaining the state of “what is,” this analysis did not shed light on agency challenges to achieving a 20% spare ratio, nor did it provide recommendations or insights on how to improve. In their three reviewed reports, Jaraiedi and Iskander (1989), Iskander et al. (1989), and Iskander and Jaraiedi (1988) provided an analytical framework for analyzing the ramifications of the FTA 20% guideline; and for developing methodologies by which different variables impacting the spare ratio can be analyzed. The methodologies and simu- lation models described are relatively simplistic, given their development in the late 1980s when transit fleets and service mixes were much less complex. However, there is much in the models that is still relevant, and that could potentially provide a foundation for new tools to inform today’s transit agencies in their determination of the optimal number of spare buses.